US00898O887B2

(12) United States Patent (10) Patent No.: US 8,980,887 B2 Yang et al. (45) Date of Patent: Mar. 17, 2015

(54) 2-ARYL Trapanietal, J. Med. Chem. 2005, 48,292-305.* IMIDAZO 1.2-APYRIDINE-3-ACETAMIDE Supplementary European Search Report dated Oct. 23, 2013 PCT/ DERIVATIVES, PREPARATION METHODS CN2011075500 in corresponding application. AND USES THEREOF S. Paul, et al., "Zinc Medicated Friedel-Crafts Acylation in Solvent Free Conditions Under Microwave Irradiation' Synthesis 2003, No. 18, pp. 2877-2881. (75) Inventors: Rifang Yang, Beijing (CN); Yunfeng Li, G. Trapani, et al., Structure-Activity Relationships and Effects on Beijing (CN); Yongzhen Li, Beijing Neuroactive Steroid Synthesis in a Series of 2-Phenylimidazo[1,2-C. (CN); Nan Zhao, Beijing (CN); Pyridineacetamide Peripheral Benzodiazepine Receptors Ligands, Liuhong Yun, Beijing (CN), Juanjuan Journal of Medicinal Chemistry, 2005, vol. 48, No. 1. Published Dec. Qin, Beijing (CN); Zhongyao Feng, 13, 2004, pp. 292-305. Beijing (CN); Youzhi Zhang, Beijing Papadopoulos V. et al., “Translocator protein (18kDa): new nomen (CN) clature for the peripheral-type benzodiazepine receptor based on its structure and molecular function.” Trends in Pharmacological Sci (73) Assignees: Institute of Pharmacology, Beijing ence, vol. 27, No. 8, p. 402-409 (2006). (CN); Toxicology Academy of Military Scarf A.M. et al., “The translocator protein (18 kDa): central nervous Medical Sciences P.L.A., China, system disease and drug design.” Journal of Medicinal Chemistry, Beijing (CN) vol. 52, No. 3, p. 581-592 (2009). Li Y. et al., Synthesis and anxiolytic effects of 2-aryl imidazo[1,2-a (*) Notice: Subject to any disclaimer, the term of this pyridine-3-acetamide derivatives, Journal of International Pharma patent is extended or adjusted under 35 ceutical Research, vol. 37, No. 4, p. 292-301 (2010). U.S.C. 154(b) by 0 days. James M.L. et al., “Development of ligands for the peripheral benzodiapene receptor.” Current Medicinal Chemistry, vol. 13, No. (21) Appl. No.: 13/805,967 17, p. 1991-2001 (2006). Samanta S. et al. “Search for Structural Requirements of 2-Phenylimidazo 1.2-Opyridineacetamide Analogs to Improve (22) PCT Filed: Jun. 9, 2011 Affinity and Selectivity towards Central and/or Peripheral Benzodiazepine Receptors.” Internet Electronic Journal of Molecu (86). PCT No.: PCT/CN2011/075500 lar Design, vol. 6, issue 7, p. 183-189 (2007). S371 (c)(1), Taliani S. et al. “Translocator protein ligands as promising therapeu (2), (4) Date: Apr. 18, 2013 tic tools for anxiety disorders.” Current Medicinal Chemistry, vol. 16, No. 26, p. 3359-3380 (2009). Rupprecht R. et al. “Translocator protein (18 kD) as target for (87) PCT Pub. No.: WO2011/160548 anxiolytics without benzodiazepine-like side effects.” Science vol. PCT Pub. Date: Dec. 29, 2011 325, p. 490-495 (2009). (Continued) (65) Prior Publication Data US 2013/02O3754 A1 Aug. 8, 2013 Primary Examiner — Wu-Cheng Winston Shen Assistant Examiner — Jean Cornet (30) Foreign Application Priority Data (74) Attorney, Agent, or Firm — Brinks Gilson & Lione Jun. 25, 2010 (CN) ...... 2010 1 0209752 (57) ABSTRACT (51) Int. Cl. Disclosed are 2-arylimidazol-2-alpyridine-3-acetamide A 6LX3/535 (2006.01) derivatives represented by formula I, their tautomer, racemate CO7D 47L/04 (2006.01) or optical isomer, their pharmaceutically acceptable salt, or (52) U.S. Cl. their solvates, wherein R', R, R and Rare defined as in the CPC ...... C07D 471/04 (2013.01) specification. Preparation methods of said compounds and USPC ...... 514/233.2: 514/300; 435/375; 54.6/121: use of said compounds in treating and/or preventing central 544f127 nervous system disease associated with TSPO functional dis (58) Field of Classification Search order USPC ...... 514/233.2, 300; 435/375; 54.6/121: 544f127 See application file for complete search history. (56) References Cited

FOREIGN PATENT DOCUMENTS

CN 1858.050 A 11, 2006 CN 101.336242 A 12/2008 WO WO99,51594 10, 1999 WO WO 2008022396 A1 * 2/2008 OTHER PUBLICATIONS STN Accession No. 2006: 1186013 CAPLUS, 2006.* 19 Claims, 6 Drawing Sheets US 8,980,887 B2 Page 2

(56) References Cited G. Trapani, et al., “Synthesis and Binding Affinity of 2-Phenylimidazo (1.2- a pyridine Derivatives for both Central and OTHER PUBLICATIONS Peripheral Benzodiazepine Receptors. A New Series of High-Affin ity and Selective Ligands for the Peripheral Type'. J. Med. Chem. Kita A. et al., “Lack of tolerance to anxiolysis and withdrawal symp- 1997, vol. 40, pp. 3109-31 18. toms in mice repeatedly treated with AC-5216, a selective TSPO Y. Sumalatha, et al., “Synthesis and Spectral Characterization of ligand.” Progress in Neuro-Psychopharmacology and Biological Process-Related Substances to the Hypnotic Agent Zolpidem'. Psychiatry, vol. 33, p. 1040-1045 (2009). ARKATUSA, Inc., ARKIVOC-2009 (vii), pp. 143-149. Notification of Reexamination of Chinese Application No. 201010209752.0. With English translation. * cited by examiner U.S. Patent Mar. 17, 2015 Sheet 1 of 6 US 8,980,887 B2

Fig. 1

sfiu?ssouogouequun.N (uæquunu)

11"(mg/kg)

Fig. 2 U.S. Patent Mar. 17, 2015 Sheet 2 of 6 US 8,980,887 B2

DW 30 0.1 0.3 DMI (mg/kg) 8# (mg/kg) Fig. 3

100

5 O

O O 0.1 0.1 YL-IPA 08(mg/kg) O 3 O 3 PK11195(mg/kg) Fig. 4 U.S. Patent Mar. 17, 2015 Sheet 3 of 6 US 8,980,887 B2

Fig. 5 U.S. Patent US 8,980,887 B2

30

O

O

O

Fig. 6

U.S. Patent Mar. 17, 2015 Sheet 6 of 6 US 8,980,887 B2

0.6

re Eg St 0.4 E --- - s Ee E - Ee . E. 0.0 E DW ? 3 10 YL-IPAO8(mg/kg) Fig. 9

3 al 5 E. E 2 E C at 1 E O - 2 e E

O OW 3. 10 YL-PAO8(mg/kg)

Fig. 10 US 8,980,887 B2 1. 2 2-ARYL called as mitochondrial benzodiazepine receptor (MBR). The IMIDAZO 1.2-APYRIDINE-3-ACETAMIDE whole structure of the receptor complex comprises a translo DERIVATIVES, PREPARATION METHODS cator protein 18 KDa (TSPO) located at mitochondrial outer AND USES THEREOF membrane, and TSPO as the minimum functional unit of PBR/MBR can combine with pharmaceutical ligand and cho CROSS-REFERENCE TO RELATED lesterol and exert important functions (Trends PharmacolSci, APPLICATIONS 2006, 27(8): 402-409; J Med Chem, 2009, 52(3): 581-592). TSPO has potential value in treatment of anxiety. After The present application is a S371 national stage application TSPO combines with corresponding ligand, it can promote of PCT International Application No. PCT/CN2011/075500, 10 the entrance of cholesterol into mitochondria, and stimulate filed Jun. 9, 2011, which application claims a right of priority biosynthesis of neurosteroids, while neurosteroids can act on to Chinese Patent Application No. 201010209752.0, filed GABA-A receptor and produce anxiolytic effects, but do not Jun. 25, 2010, both of which are incorporated herein by produce apparent side effects. reference in their entirety. At present, TSPO ligands are very widely studied, and it 15 has been reported that many compounds exert good activity in TECHNICAL FIELD vivo and in vitro, and TSPO ligands having relatively high affinity and selectivity are reported as well. According to their The present invention belongs to medical chemical field, chemical structure, there are mainly benzodiazepines (e.g., and relates to 2-arylimidazol-2-alpyridine-3-acetamide 4'-chlorodiazepam (Ro5-4864), isoquinoline amides, ben derivatives, their preparation methods and uses. The present Zothiazepines, benzoxazepines, indole acetamides (e.g., invention further relates to a pharmaceutical composition FGIN), imidazopyridine acetamides, aryloxyaniline deriva comprising a compound of Formula I, its tautomer, its race tives, pyrazolopyrimidine acetamides, 3-indolyloxamides, mic or optical isomer, its pharmaceutically acceptable salt, or 2-arylpyrimidine derivatives, and 2-aryl-8-oxypurine deriva its Solvate, a method for treatment and/or prophylaxis of a tives. These ligands have roughly same basic structure, and central nervous system disease associated with TSPO func 25 can be concluded as: containing one hydrogen bond donator tional disorder, and a method for combating cell apoptosis in (81, usually amide), two lipophilic areas (PAR and FRA) on Vivo or in vitro, combating a tumor, inflammatory immuno mother ring backbone, and another lipophilic area (LA) bind regulation, neuroprotection, or regulating TSPO activity. ing to receptor via allosterism (Curr Med Chem, 2006, 13(17): 1991-2001. Curr Med Chem, 2009, 16(26): 3359 Formula I 30 3380.). In corresponding animal models and clinical studies, some of the selective TSPO ligands had been showed potential values in creating new drugs with TSPO as target. For example, PK1 1195, a TSPO/PBR selective antagonist, has 35 been widely used in finding new types of TSPO ligands and activity comparison as a tool drug. In addition, Emapunil (AC-5216, XBD173) has high selectivity and affinity, less side effects, no remarkable withdrawal symptoms and drug withdraw rebounding symptoms, and thus enters phase II 40 clinical research (Science 2009, 325, 490-195; Prog Neuro BACKGROUND ART Psychoph, 2009, 33, 1040-1045.). However, most of these compounds have poor pharmacokinetics, low bioavailability, Anxiety disorder has main symptoms such as panic, uneasy difficulty in penetrating blood brain barrier. Hence, it is still and repeated anxieties, and patients under mental disorder needed to find better TSPO ligands. state cannot exert normal living ability and effectively work, 45 and long-term of diseases may grievously influence patients CONTENTS OF THE INVENTION health and daily life, and even may induce more serious consequences such as Suicide. In addition, the later phase of One aspect of the present invention relates to a compound anxiety is usually accompanied with depression symptoms. of Formula I, its tautomer, its racemic or optical isomer, its Some statistical results show that the patients with anxiety are 50 pharmaceutically acceptable salt (a salt acceptable in phar of 8-13% of the world population, and most of them are lack macy, which is water Soluble), or its Solvate, of necessary medicinal intervention and treatment. Hence, it is very important to develop medicaments with good activity against anxiety and depression. Traditional drugs such as diazepam, alpidem are widely 55 used in clinic for treatment of anxiety and depression, but these previous drugs can not only act on peripheral benzodi azepine receptor (PBR), but also act on central benzodiaz epine receptor (CBR), so that they may frequently induce side effects such as sedation, hypnosis, amnesia, muscle relax 60 ation, tolerance, and may easily induce drug dependence and addiction. Thus, it is urgent to have anxiolytics drugs with higher target specificity, less side effects and lower drug wherein: dependence. R" is selected from ethyl, propyl, butyl, and methoxyethyl: Some researches show that PBR is mainly on cell mito 65 R’ is selected from benzyl, 2-pyridinylmethyl, 3-pyridinyl chondrial membrane, and is one of pivotal components of cell methyl, 4-pyridinylmethyl, 2-morpholinylethyl, and 3-mor mitochondrial membrane receptor complex, and thus is also pholinylpropyl; US 8,980,887 B2 3 4 R. Rare independently selected from H, halogen, alkyl, pharmaceutically acceptable salt, or its solvate, is selected substituted hydrocarbonyl, alkenyl, substituted alkenyl, phe from the following Compounds 1-28: nyl, substituted phenyl, heteroaryl, substituted heteroaryl, N-benzyl-N-ethyl-2-(4-chlorophenyl)-7-methylimidazol, C-C alkoxyl, Cs-Co aryloxy, Substituted aryloxy, C-C, 2-alpyridine-3-acetamide; alkylamino, Cs-Co arylamino, Substituted arylamino, di -ethyl-N-(2-pyridinylmethyl)-2-(4-chlorophenyl)-7-meth (C-C alkyl)amino, di-(Cs-Co aryl)amino, di-(substituted ylimidazol-2-alpyridine-3-acetamide. hydrochloride; aryl)amino, Co hydrocarbonylacyloxy, Cao arylacyloxy, -ethyl-N-(3-pyridinylmethyl)-2-(4-chlorophenyl)-7-meth Co hydrocarbonylacylamino, Cao arylacylamino, car ylimidazol-2-alpyridine-3-acetamide. hydrochloride; boxyl, Cohydrocarbonyloxy formyl, C-aryloxy formyl. -ethyl-N-(4-pyridinylmethyl)-2-(4-chlorophenyl)-7-meth aminoformyl, Co hydrocarbonylaminoformyl, or Co 10 ylimidazol-2-alpyridine-3-acetamide. hydrochloride; arylaminoformyl; wherein the heteroaromatic cycle is a -(2-methoxyethyl)-N-(2-pyridinylmethyl)-2-(4-chlo monocyclic or fused aromatic hydrocarbonyl having 1-3 het rophenyl)-7-methylimidazol-2-alpyridine-3-acetamide. eroatoms selected from N, O or S, each of the substituents of hydrochloride: groups having Substituents is selected from halogen, N-(2-methoxyethyl)-N-(3-pyridinylmethyl)-2-(4-meth hydroxyl, cyano, nitro, Ce alkyl, C. alkoxyl, C. alky 15 ylphenyl)-7-methylimidazol-2-alpyridine-3-acetamide. lthio, mono- or di- or tri-halogenated C. alkyl, amino, C. hydrochloride: alkylamino, Cohydrocarbonylacyloxy, Co hydrocarbo N-benzyl-N-ethyl-2-(3,4-dichlorophenyl)-7-methylimidazo nylacylamino, Cao arylacyloxy, and Co-o arylacylamino. 1.2-alpyridine-3-acetamide; According to the present invention, the pharmaceutically N-ethyl-N-(2-pyridinylmethyl)-2-(3,4-dichlorophenyl)-7- salt of the compound of Formula I can be an acid addition salt methylimidazol-2-alpyridine-3-acetamide.hydrochlo or a salt formed with an alkali. The acid addition salt can bean ride; inorganic acid salt, including but not being limited to hydro N-ethyl-N-(3-pyridinylmethyl)-2-(3,4-dichlorophenyl)-7- chloride, Sulfate, phosphate, or hydrobromide, etc.; or an methylimidazol-2-alpyridine-3-acetamide.hydrochlo organic acid salt, including but not being limited to acetate, ride; oxalate, citrate, gluconate. Succinate, tartrate, p-tosylate, N-ethyl-N-(4-pyridinylmethyl)-2-(3,4-dichlorophenyl)-7- mesylate, benzoate, lactate, or maleate, etc.; the salt of the 25 methylimidazol-2-alpyridine-3-acetamide.hydrochlo compound of Formula I formed with an alkalican be an alkali ride; metal salt, including but not being limited to lithium salt, N-(2-methoxyethyl)-N-(2-pyridinylmethyl)-2-(3,4-dichlo Sodium slat, or potassium salt, or an alkaline earth metal salt, rophenyl)-7-methylimidazol-2-alpyridine-3-acetamide. including but not being limited to calcium salt or magnesium hydrochloride: salt, oran organic alkali base, including but not being limited 30 N-(2-methoxyethyl)-N-(3-pyridinylmethyl)-2-(3,4-dichlo to diethanolamine salt or choline salt, etc.; or a chiral alkali salt, including but not being limited to alkylphenylamine salt, rophenyl)-7-methylimidazol-2-alpyridine-3-acetamide. etc. hydrochloride: The solvate of the compound of the present invention can -benzyl-N-ethyl-2-(4-methylphenyl)-7-methylimidazo1, be a hydrate, and optionally comprises other crystallization 2-alpyridine-3-acetamide; Solvents such as alcohols, including but not being limited to 35 -ethyl-N-(2-pyridinylmethyl)-2-(4-methylphenyl)-7-meth ethanol. ylimidazol-2-alpyridine-3-acetamide. hydrochloride; According to the present invention, the compound of For -ethyl-N-(3-pyridinylmethyl)-2-(4-methylphenyl)-7-meth mula I can be present in cis/trans isomers, and the present ylimidazol-2-alpyridine-3-acetamide. hydrochloride; invention relates to cis-form and trans-form and a mixture of -ethyl-N-(4-pyridinylmethyl)-2-(4-methylphenyl)-7-meth 40 ylimidazol-2-alpyridine-3-acetamide. hydrochloride; these forms. If necessary, the preparation of single stereoiso -(2-methoxyethyl)-N-(2-pyridinylmethyl)-2-(4-meth mer can be performed by resolution of mixture according to ylphenyl)-7-methylimidazol-2-alpyridine-3-acetamide. conventional methods, or by stereo-selective synthesis. If hydrochloride: there is a mobile hydrogen atom, the present invention can -(2-methoxyethyl)-N-(3-pyridinylmethyl)-2-(4-meth also relate to the tautomers of the compound of Formula I. ylphenyl)-7-methylimidazol-2-alpyridine-3-acetamide. In one embodiment of the present invention, R has 1-2 45 hydrochloride: substituents, and R is at 4-, 5-, 6-, or 7-position of imidazo -benzyl-N-ethyl-2-(4-methoxyphenyl)-7-methylimidazo 1,2-alpyridine ring; R has 1-3 substituents, and R is at o-, 1.2-alpyridine-3-acetamide; m- or p-position of benzene ring. -ethyl-N-(2-pyridinylmethyl)-2-(4-methoxyphenyl)-7-me In one embodiment of the present invention, R, R are thylimidazo 1,2-alpyridine-3-acetamide. hydrochloride; independently selected from F, Cl, Br, I, C-C alkyl, C-C, 50 alkoxylethyl, and C-C alkoxyl. -ethyl-N-(3-pyridinylmethyl)-2-(4-methoxyphenyl)-7-me In one embodiment of the present invention, R, R are thylimidazo 1,2-alpyridine-3-acetamide. hydrochloride; independently selected from F, Cl, Br, C-C alkyl, and C-C, -ethyl-N-(4-pyridinylmethyl)-2-(4-methoxyphenyl)-7-me alkoxyl. thylimidazo 1,2-alpyridine-3-acetamide. hydrochloride; In one embodiment of the present invention, R, R are N-(2-methoxyethyl)-N-(2-pyridinylmethyl)-2-(4-methox independently selected from F, Cl, methyl, ethyl, methoxy 55 yphenyl)-7-methylimidazol-2-alpyridine-3-acetamide. ethyl, methoxy, and ethoxy. hydrochloride: In one embodiment of the present invention, the compound N-(2-methoxyethyl)-N-(3-pyridinylmethyl)-2-(4-meth of Formula I, its tautomer, its racemic or optical isomer, its oxyphenyl )-7-methylimidazol-2-alpyridine-3-acetamide pharmaceutically acceptable salt, or its solvate, respectively -hydrochloride; meet one more of following items (1) to (4): 60 N-(2-methoxyethyl)-N-(2-morpholinylethyl)-2-(4-meth (1) R' is ethyl or methoxyethyl: ylphenyl)-7-methylimidazol-2-alpyridine-3-acetamide. (2) R is benzyl, 2-pyridinylmethyl, 3-pyridinylmethyl, hydrochloride: 4-pyridinylmethyl, or 2-morpholinylethyl: N-(2-methoxyethyl)-N-(2-morpholinylethyl)-2-(4-meth (3) R is 6-methyl or 7-methyl: ylphenyl)-6-methylimidazol-2-alpyridine-3-acetamide. (4) R' is 4-chloro, 3,4-dichloro, 4-methyl, or 4-methoxy. 65 hydrochloride: In one embodiment of the present invention, the compound N-ethyl-N-(4-pyridinylmethyl)-2-(4-methylphenyl)-6-meth of Formula I, its tautomer, its racemic or optical isomer, its ylimidazol-2-alpyridine-3-acetamide. hydrochloride; and US 8,980,887 B2 5 6 N-ethyl-N-(4-pyridinylmethyl)-2-(4-chlorophenyl)-6-meth- The structural formulas of the above Compounds 1-28 are ylimidazol-2-alpyridine-3-acetamide.hydrochloride. shown in Table 1: TABLE 1

Structural formulas of Compound 1-28 (as prepared in Example 13-40)

No Compound name Structural formula

1 N-benzyl-N-ethyl-2-(4-chlorophenyl)- 7-methylimidazol-2-apyridine-3-acetamide 21

%YN O l C

2 N-ethyl-N-(2-pyridinylmethyl)-2-(4-chlorophenyl)- 7-methylimidazo[1,2-alpyridine-3-acetamidehydrochloride 21 %YN | O leN ear HCI l C

3 N-ethyl-N-(3-pyridinylmethyl)-2-(4-chlorophenyl)- 7-methylimidazo[1,2-alpyridine-3-acetamidehydrochloride 21 N %YN O | N HC le l C

4 N-ethyl-N-(4-pyridinylmethyl)-2-(4-chlorophenyl)- 7-methylimidazo[1,2-alpyridine-3-acetamidehydrochloride 21 HCI N %YN N O le

N

C

US 8,980,887 B2 15 16 TABLE 1-continued

Structural formulas of Compound 1-28 (as prepared in Example 13-40)

No Compound name Structural formula

21 N-ethyl-N-(3-pyridinylmethyl)-2-(4-methoxyphenyl)- 7-methylimidazol-2-alpyridine-3-acetamidehydrochloride 21

%YN f Y HCI O le elee l V

22 N-ethyl-N-(4-pyridinylmethyl)-2-(4-methoxyphenyl)- 7-methylimidazol-2-alpyridine-3-acetamidehydrochloride 21 HCI N %YN | O le l V 23 N-(2-methoxyethyl)-N-(2-pyridinylmethyl)-2-(4-methoxyphenyl)- 7-methylimidazol-2-alpyridine-3-acetamidehydrochloride 21 %YN O | leN ere HCI N

V N

24 N-(2-methoxyethyl)-N-(3-pyridinylmethyl)-2-(4-methoxyphenyl)- 7-methylimidazol-2-alpyridine-3-acetamidehydrochloride 21 2 | YN Hc N N O le

US 8,980,887 B2 19 In one embodiment of the present invention, the compound is N-ethyl-N-(2-pyridinylmethyl)-2-(3,4-dichlorophenyl)-7- methylimidazo 1,2-alpyridine-3-acetamide.hydrochloride II and N-ethyl-N-(4-pyridinylmethyl)-2-(3,4-dichlorophenyl)- 7-methylimidazo 1,2-alpyridine-3-acetamide.hydrochlo ride. Another aspect of the present invention relates to a method for preparing the above compound of Formula I, its tautomer, its racemic or optical isomer, its pharmaceutically acceptable salt, or its solvate, comprising the following steps: 10 a) converting an aromatic hydrocarbon compound of For mula VIII: e) in the presence or absence of a catalyst, Such as 4-dim VIII ethylaminopyridine, reacting the carboxylic compound of 15 Formula II as obtained in step d) with an amine compound of Formula III in the presence of a condensing agent (Such as ( ) 1-ethyl-3-(3-diisopropylaminopropyl)carbodiimide (EDC) or 1,3-dicyclohexylcarbodiimide (DCC)): via Friedel-Crafts acetylation to form a ketone compound of Formula VII: III VII ( ) R21 NR, 25 to obtain a compound of Formula I: b) reacting the ketone compound VII with bromine under the catalysis of aluminum trichloride to form a bromide, not being separated, reacting with an aminopyridine compound of Formula VI, 30

VI

35

R2 -N under heating and presence of an alkali (Such as Sodium R1 carbonate) to forman imidazopyridine compound of Formula V: 40 According to the teachings of the present invention, the compound of Formula I of the present invention can be Syn thesized on the basis of the knowledge in the art. In one embodiment of the method for preparing the com 45 pound of Formula I of the present invention, a corresponding substituted aromatic hydrocarbon is subjected to Friedel c) reacting the imidazopyridine compound V with dim Crafts acetylation, bromination, then condensation with ethylamine and formaldehyde aqueous solution in acetic acid 2-aminopyridine to form a corresponding 2-arylimidazol-2- to form a Mannich base, separating via filtration, then react apyridine V, the latter is then subjected to Mannich reaction ing with iodomethane to form a quaternary ammonium salt of 50 and methylation to form a corresponding quaternary ammo Formula IV: nium salt IV of 3-methylaminomethyl, then reacts with a cyanide, then is subjected to hydrolysis and acidification to IV form a corresponding 2-arylimidazol-2-alpyridine-3-acetic 55 acid precursor II, and finally Subjected to condensation with a / \, S1). substituted secondary amine in the presence of 1-ethyl-3-(3- R4,o N N 21 dimethylaminopropyl)carbodiimide (EDC) to obtain an Ie amide compound of Formula I. The reaction scheme is as 91 follows: /N 60 d) reacting the quaternary ammonium salt IV with a cya ( ) AcCl / \ O Br2 nide (such as sodium cyanide or potassium cyanide) to form R41K CICl3 R41S a corresponding nitrile, then hydrolyzing in the presence of a 65 strong base, and acidifying to form a carboxylic compound of VIII VII Formula II: US 8,980,887 B2 21 22 -continued a) converting an aromatic hydrocarbon compound of For mula VIII:

O N= R, 5 VIII / \ VI R-S.o ( ) Br via Friedel-Crafts acetylation using Succinic anhydride to / \ N-n--Rs - 1) HCHO, (CH),NH - " form a ketonic acid compound of Formula VII': R41S N- 2 2) CHI VIII

OH: NN-n --Rs 15 R4 -X GN-4 21 1) NaCN He I 2) NaOHaq 8- 2O /N b) Subjecting the above ketonic acid compound of Formula VIII' to bromination with bromine to form abrominated acid IV compound of Formula VII': / \ NS1S -NaH N --R, R RI 25 VII RQ N4 III EDC OH: O 30 Br O HO II

c) reacting the above brominated acid compound of For mula VII' with a chloroformate (such as ethyl chloroformate 35 or isobutyl chloroformate) to form a mixed acid anhydride, then reacting with an amine of Formula III

III 40 R21 NRI I in the presence or absence of a catalyst (such as DMAP), The Substituted secondary amine is prepared from a corre- 45 and in the presence of an alkali to form a bromonated amide sponding primary amine and a Substituted aldehyde via compound of Formula II': reductive alkylation or catalytic hydrogenation; or prepared by converting a substituted alcohol into its halogenide or II active ester, then reacting with a corresponding primary O ?' N amine. The reaction schemes are as follows: 50 N V R4 II R2 2 Br O - NH,In 12 1) Ar-CHO,s EtOH Y Air R1 2) NaBH4 11 n-1 55 III d) Subjecting the above bromonated amide compound of NH2 H Formula II' and an aminopyridine compound of Formula VI: R2 OH SOX 2 -Y He-R1 R11 N NR2 or: R'SOCl, base III 60 VI Y =X or SOR (X = Cl, Br)

Optionally, the method for preparing the above compound of Formula I, its tautomer, its racemic or optical isomer, its 65 pharmaceutically acceptable salt, or its Solvate, comprises the to condensation in the presence of an alkali to prepare a following steps: compound of Formula I: US 8,980,887 B2 24 -continued NS1S 1) NaOH (aq) R1 XV- KON N4 o2) HO"

O

10 V IV

According to the preparation method of the present inven tion, the amine compound of Formula III is prepared from a 15 primary amine R-NH2 and a corresponding aldehyde via reductive amination or catalytic hydrogenation amination; or prepared by reacting a corresponding alcohol R’ OH with halogenated Sulfoxide to form a corresponding halogenide R X, or with sulfonyl chloride to form an active ester R’ OSO-R, then reacting with a primary amine R' NH in the presence or absence of an alkali to prepare the amine III. In another embodiment of the method for preparing the compound of Formula I of the present invention, a substituted 25 aromatic hydrocarbon VIII is subjected to Friedel–Crafts acetylation using Succinic anhydride to form 4-aryl-4-oxy butanoic acid VIII', then bromination to form abromide VII", then conversion to form an ester VI", then condensation with a corresponding 2-aminopyridine V to form 2-arylimidazol, 30 2-alpyridine IV', the hydrolysis to form a corresponding acid II, and finally reaction with an amine III in the presence of condensing agent EDC to form the target compound amide I. The reaction scheme is as follows: 35 In another embodiment of the method for preparing the compound of Formula I of the present invention, a substituted O aromatic hydrocarbon VIII is subjected to Friedel–Crafts acetylation using Succinic anhydride to form 4-aryl-4-oxy O He butanoic acid VIII', then bromination to form abromide VII", (1 ) AlCl3 40 then conversion by mixed anhydride method to forman amide R\= II", then condensation with a corresponding 2-aminopyridine VIII O V to form the target compound 2-arylimidazol-2-alpyridine 3-acetamide I. The reaction scheme is as follows: / \ A 45 OH Br2 ya O R4 N AlCl3 O R4 - -- O -> VIII 50 O 21 / \ CHOH VIII O OH He ya- H2SO4) O R4 OH Br O 55 N Br RU He VII S2 O

VIII 60 O OH CICOEt ---n - N - Na2CO3/NaHCO3 R -NS Br O 2 Br O R2 RI 65 VI VII III US 8,980,887 B2 25 26 -continued urea, calcium carbonate, porcellanite, microcrystalline cellu R3 31 lose, aluminum silicate; wetting agents and binding agents, O HN \ / Such as water, glycerol, polyethylene glycol, ethanol, pro M N panol, starch slurry, dextrin, syrup, honey, glucose solution, N Arabic gum gel, gelatin gel, carboxylmethylcellulose N Y. VI -- Sodium, shellac, methylcellulose, potassium phosphate, R'- Br O Na2CO3/NaHCO polyvinylpyrrolidone; disintegrants, such as dry starch pow der, alginate, agar powders, laminarin, Sodium hydrogen car bonate and citric acid, calcium carbonate, polyoxyethylene 10 sorbitol fatty acid ester, sodium dodecylsulfonate, methylcel lulose, ethylcellulose; disintegration inhibitors, such as Sucrose, glycerol tristearate, cocoa butter, hydrogenated oil; absorption enhancers, such as quaternary ammonium salts, 15 Sodium dodecylsulfate; lubricants, such as talc powder, silica, corn Starch, Stearate, boric acid, liquid paraffin, polyethylene glycol. The tablets can be further processed to form coating tablets, such as Sugar coated tablets, thin film coated tablets, enteric coating tablets, or bilayer tablets and multilayer tab lets. In order to manufacture pills of administration unit, various carriers known in the art can be widely used. The In the method for synthesis of the compound of Formula I examples of these carriers include, for example, diluents and according to the present invention, the raw materials used in absorbents, such as glucose, lactose, starches, cocoa butter, the reactions are all obtainable by those skilled in the art hydrogenated vegetable oil, polyvinylpyrrolidone, Gelucire, according to the existing knowledge, or can be prepared by kaolin, talc powder, etc.; binding agents such as Arabic gum, known methods in the documents in the art, or commercially tragacanth gum, gelatin, ethanol, honey, liquid Sugar, rice available. The intermediates, raw materials, reagents and paste or panada; disintegrants. Such as agar powders, dry reaction conditions used in the above reaction schemes can be starch powder, alginate, Sodium dodecylsulfonate, methyl cellulose, ethylcellulose. In order to manufacture Supposito Suitably changed by those skilled according to the knowledge 30 in the art. Otherwise, those skilled in the art can prepare other ries of the administration unit, various carriers known in the compounds of Formula I that are not specifically listed in the art can be widely used. The examples of these carriers text according to the preparation method of the second aspect include, for example, polyethylene glycol, lecithin, cocoa of the present invention. butter, higher alcohol, esters of higher alcohols, gelatin, semi The further another aspect of the present invention relates 35 synthesized glycerides. In order to manufacture capsules of to a pharmaceutical compound, which comprises at least one the administration unit, the compound of Formula I or its the above compound of Formula I, its tautomer, its racemic or stereoisomeras effective component is mixed with the above optical isomer, its pharmaceutically acceptable salt, or its various carriers, and the resultant mixture is placed in hard Solvate, and optionally a pharmaceutically acceptable carrier gelatin capsules or soft capsules. The compound of Formula or excipient. 40 I or its stereoisomer as effective component can also be pro The pharmaceutical composition can be applied to ani cessed to form microcapsules, which can be suspended in an mals, preferably mammals, especially human. Generally, the aqueous medium to form a suspension, or filled in hard cap pharmaceutical composition of the present invention com Sules or converted into injections. In order to manufacture of prises 0.1-90 wt.% of the compound of Formula I and/or its injection preparations of the administration unit, such as solu physiologically acceptable salt. The pharmaceutical compo 45 tions, emulsions, lyophilized powder for injection and Sus sition can be prepared according to known methods in the art. pensions, various carriers known in the art can be widely For this purpose, if necessary, the compound of Formula I used, for example, water, ethanol, polyethylene glycol, 1.3- and/or stereoisomer thereof is combined with one or more propanediol, ethoxylated isostearyl alcohol, multi-oxidized Solid or liquid pharmaceutically acceptable excipient and/or isostearyl alcohol, polyoxyethylene sorbitol fatty acid esters. adjuvant, to prepare a Suitable administration form or dosage 50 In addition, in order to manufacture isosmotic injection solu form for human use. tions, a suitable amount of sodium chloride, glucose or glyc The compound of Formula I or the pharmaceutical com erol can be added to injection preparations. Further, conven position comprising the same according to the present inven tional co-solvents, buffer agents, pH regulators can also be tion can be administered in unit dosage form, via administra added. tion route Such as intestinal route or parenteral route, such as 55 In addition, if desired, coloring agents, preservatives, per oral, muscle, Subcutaneous, nasal cavity, mouth mucosa, fumes, correctant, Sweeting agents or other materials can also skin, peritoneum or rectum. The administration dosage form be added. can be for example tablets, capsules, dropping pills, aerosols, The term “composition' in the text refers to a product pills, powders, Solutions, Suspensions, emulsions, granules, comprising various components in designated amounts, and liposomes, transdermal agents, buccal tablets, Suppositories, 60 any product directly or indirectly derived from various com lyophilized powders, etc., can be normal preparations, Sus ponents in designated amounts in combination. tained release preparations, controlled release preparations, The further aspect of the present invention relates to a use and various particle drug delivery systems. In order to manu of the compound of Formula I, its tautomer, its racemic or facture tablets of unit dosage form, various carriers known in optical isomer, its pharmaceutically acceptable salt, or its the art can be widely used. The examples of carriers can be 65 solvate, as TSPO ligand. diluents and absorbents, such as starches, dextrin, calcium The further aspect of the present invention relates to a use Sulfate, lactose, mannitol. Sucrose, sodium chloride, glucose, of the compound of Formula I, its tautomer, its racemic or US 8,980,887 B2 27 28 optical isomer, its pharmaceutically acceptable salt, or its physician within the range of reliable medical decisions. As Solvate, in manufacture of a medicament or reagent for regu for any specific patients, the specific therapeutically amount lating TSPO activity. must be determined based on various factors, including the The further aspect of the present invention relates to a use diseases to be treated and severity thereof, the activity of the of the compound of Formula I, its tautomer, its racemic or 5 used specific compound, the used specific composition, the optical isomer, its pharmaceutically acceptable salt, or its age, body weight, general health status, gender and food of Solvate in manufacture of a medicament for prophylaxis or patient, the administration time and route and excretory rate treatment of a central nervous system disease associated with of the used specific compound, the drug(s) administered in TSPO dysfunction. Specifically, the central nervous system combination or simultaneously with the specific compound, disease associated with TSPO dysfunction is depression, 10 anxiety, mania, cognitive defect, Schizophrenia, pains, con and similar factors well known in the art of medicine. For Vulsion, drug dependence, sleep disorders, ingestion disor example, it is a common method in the art to increase gradu ders, alcoholism, nerve injury, or stress disorders. ally the dose of compound from a level lower than that for The further aspect of the present invention relates to a use achieving desired therapeutical effects to a level enough to of the compound of Formula I, its tautomer, its racemic or 15 achieve the desired therapeutical effects. In general, the dose optical isomer, its pharmaceutically acceptable salt, or its of a compound of Formula I for mammals especially human Solvate, in manufacture of a medicament for combating cell can be 0.001-1000 mg/kg body weight per day, such as 0.01 apoptosis, anti-tumors, inflammatory immunoregulation, or 100 mg/kg body weight per day, 0.01-10 mg/kg body weight neuroprotection. per day. The further aspect of the present invention relates to a The compound of Formula I, its tautomer, its racemic or method for prophylaxis and/or treatment of a central nervous optical isomer, its pharmaceutically acceptable salt, or its system disease associated with TSPO dysfunction, such as Solvate, according to the present invention, can effectively depression, anxiety, cognitive defect, convulsion, drug prevent and/or treat the various diseases and disorders as dependence, pains, sleep disorders, ingestion disorders, alco mentioned in the present invention. holism, as well as for anti-cell apoptosis, anti-tumors, inflam 25 The inventors find via researches that the compound of matory immunoregulation, neuroprotection, or regulating Formula I has function of regulating TSPO, so that this type of TSPO activity in vivo or in vitro, the method comprises a step compounds can be used in a central nervous system disease of administering a subject in Such need a prophylactically associated with TSPO dysfunction, such as depression, anxi and/or therapeutically effective amount of the compound of ety, cognitive defect, convulsion, drug dependence, pains, Formula I, its tautomer, its raceme or stereoisomer, its phar 30 sleep disorders, ingestion disorders, alcoholism, as well as for maceutically acceptable salt, or its Solvate. The medicament anti-cell apoptosis, anti-tumors, inflammatory immunoregu is useful in animals, preferably mammals, especially human. lation, neuroprotection. Further synthesis and researches The dose of the compound of Formula I of the present indicate that a pharmaceutically acceptable salt of a derivative invention, its tautomer, its racemic or optical isomer, its phar of the present invention form with a suitable inorganic acid or maceutically acceptable salt, or its solvate, depends on many 35 organic acid or with an inorganic alkali or organic alkali factors, such as property and severity of the disease to be would also have effect in regulating TSPO function. prevented or treated, patients or animals gender, age, body All documents as cited in the present invention are incor weight and individual reaction, the specific compound to be porated in the text by reference, and if the meanings of these used, administration route, and administration frequency. The documents are inconsistent with the present invention, the dose can be administered in single dose form or in several 40 expressions of the present invention should be used. In addi batches, such as 2-, 3- or 4-batches. tion, the terms and phrases used in the present invention has The actual dose levels of various active components in the common meanings well known by those skilled in the art, pharmaceutical composition of the present invention can be nevertheless, these terms and phrases are further explained changed so that the expected therapeutic effects can be and illustrated in the invention. If the mentioned terms and achieved via the resultant amount relative to specific patient, 45 phrases have meanings different from those known in the art, composition and administration manner. The dose level must the meanings present in the present invention should be used. be selected according to the activity of the specific com The terms “halo”, “halogen”, “Hal” or “halogenated” refer pound, administration route, severity of disease to be treated, to fluorine, chlorine, bromine and iodine. patient’s condition and medical history. However, the prac In the present invention, the used terms “alkyl”, “alkenyl tice in the art is that the dose of compound gradually increases 50 and “alkynyl have the common meanings well known in the from a level lower than that for achieving the desired thera art, that is, they are straight or branched hydrocarbon groups, peutical effects to a dose capable of achieving the desired for example but not limited to methyl, ethyl, propyl, isopro therapeutical effects. pyl. n-butyl, sec-butyl, tert-butyl, allyl, propenyl, propinyl, In the aforementioned or other treatment and/or prophy etc., and the “alkyl, "alkenyl and “alkynyl can be collec laxis, a compound of the present invention in atherapeutically 55 tively called as “hydrocarbonyl' or “aliphatic hydrocarbo and/or prophylactically effective amount can be used in form nyl. In a preferable embodiment of the present invention, the of pure compound, or inform of pharmaceutically acceptable term “hydrocarbonyl refers to alkane, including alkyl and esters or prodrugs thereof (if they exist). Alternatively, the cyclic alkyl, especially alkyl such as C-C alkyl. compound can be administered via a pharmaceutical compo In the present invention, the term “substituted or unsubsti sition comprising the compound and one or more pharmaceu 60 tuted C-C alkyl refers to a substituted or unsubstituted tically acceptable excipients. The term a compound of the alkyl group having designated carbon atoms, its examples present invention in a “therapeutically and/or prophylacti include but are not limited to: methyl, ethyl, propyl, isopro cally effective amount’ means that the compound is in an pyl, butyl, tert-butyl, pentyl, neopentyl, hexyl. amount Sufficient to achieve prophylactically and/or thera In the present invention, the term "central nervous system peutically reasonable ratio of effect/risk. It should be under 65 disease associated with TSPO dysfunction” refers to a central stood that the total amount per day of the compound or com nervous system disease directly or indirectly induced by position of the present invention must be determined by a TSPO dysfunction, Such as depression, anxiety, mania, cog US 8,980,887 B2 29 30 nitive defect, Schizophrenia, pains, convulsion, drug depen tated near to the end of dropwise addition), after the end of dence, sleep disorders, ingestion disorders, alcoholism, nerve addition, further stirred for 20 min, added with 25 mL of injury, stress disorders, etc. water, then added with 13.5 g (0.127 mol) of solid sodium carbonate, then added with 11.5 g (0.106 mol) of solid BRIEF DESCRIPTION OF THE DRAWINGS 2-amino-4-methylpyridine, heated to 35° C., stirred over night (14 h), and terminated reaction. Added with 100 mL of FIG. 1: Effects of Example Compounds 8 and 10 on open water, stirred in ice-water bath (white solid precipitated), field spontaneous locomotor activity in mice. The results are suction filtrated, washed with water, dried to obtain II 20.28 shown in xits, n=9-10. *P<0.05 in comparison with DW g, yellow solid powder, yield 85%. m.p. 157-160° C. group. 10 b) 1-(2-(4-methoxyphenyl)-7-methylimidazo 1,2-a-3- FIG. 2: Effects of Example Compounds 11 and 13 on open pyridinyl)-N,N-dimethylamine (III): 20.28 g (0.085 mol) of field spontaneous locomotor activity in mice. The results are II was weighed, dissolved in 30 ml of acetic acid, stirred shown inxits, n=5. under room temperature, added dropwise with 14.5 g (0.106 FIG. 3: Effects of Example Compound 8 on immobility mol) of dimethylamine aqueous solution (33%), (with slight time in tail suspension test in mice. The results are shown in 15 xts, n=8-9, *P<0.05 in comparison with DW group. heat release, Solid appeared and dissolved immediately), then FIG. 4: Effects of PK1 1195 on the antidepressant-like added dropwise with 8.5 g (0.105 mol) of formaldehyde effect of Compound 8 in mice tail suspension test. The results aqueous solution (37%), after the end of addition, heated to are shown inxits, n=8-11, *P<0.05 in comparison with DW 35° C. and stirred for 2 h, stopped reaction. In ice-water bath, group; hip-0.05 in comparison with Compound 8 group. regulated with sodium hydroxide aqueous solution to reach FIG. 5: Effects of Example Compound 8 on behavior of pH 8-9, extracted with dichloromethane, washed with water, mice in elevated plus maze test. The results are shown inxits, saturated saline in order, dried with anhydrous sodium sulfate n=6, *P<0.05, **P<0.01 in comparison with DW group. overnight, evaporated to remove solvent to obtain thick liquid FIG. 6: Effects of Example Compounds 8 and 10 on behav III (crude product) 25.78 g. ior of mice in elevated plus maze test. The results are shown 25 c)-(4-methoxyphenyl)-7-methylimidazol-2-a-pyri inxits, n=9-10, *P<0.05 in comparison with DW group. dine-3-acetic acid (V): 25.78 g (0.087 mol) of III was dis FIG. 7: Effects of Example Compounds 11 and 13 on solved in 150 ml of acetone, stirred at room temperature, behavior of mice in elevated plus maze test. The results are added dropwise with 5.5 ml (0.088 mol) of iodomethane, shown inxits, n=5. solid precipitated before the end of addition, after the end of FIG. 8: Effects of Example Compound 8 on immobility 30 addition, reacted overnight (20 h), stopped the reaction. Fil time inforced swim test in rats. The results are shown inxts, tered and washed with acetone, dried to obtain 27.8 g of n=8, *P<0.05 in comparison with DW group. quaternary ammonium salt IV, crude yield 75%. "H NMR FIG. 9: Effects of Example Compound 8 on serum preg (DMSO-de, 400MHz)6:2.42(s.3H), 2.86(s.9H), 3.82(s.3H), nenolone (PREG) inforced swim rats. The results are shown inxts, n=6, *P<0.05 in comparison with DW group. 35 5.2(s. 2H), 7.00(d. 1H, J–7.00 Hz), 7.04-7.06(m, 2H), 7.50(s, FIG. 10: Effects of Example Compound 8 on serum 1H), 7.77-7.79(m, 2H), 8.82(d. 1H, J=7.00 Hz). progesterone (PROG) in forced swim rats. The results are 27.8 g (0.064 mol) of the above prepared quaternary shown inxits, n=6, P-0.05 in comparison with DW group. ammonium salt (IV) crude product was dissolved in 120 mL of a mixture solution of water and dioxane (V: SPECIFIC MODELS FOR CARRYING OUT THE 40 V=2:1), then added with 20 mL of polyethylene-400, INVENTION added with 3.1 g (0.064 mol) of sodium cyanide, heated to 85° C. and reacted for 4h, monitored with TLC until the comple The present invention is further illustrated with the follow tion of reaction. Cooled to room temperature, added with 29 ing examples, but those skilled in the art would understand the g (0.725 mol) of sodium hydroxide solid, heated to 110° C. following examples are merely used to illustrate the present 45 and refluxed for 24h, monitored until no more ammonia gas invention, rather than to limit the protection scope of the generated, stopped the reaction. Cooled, extracted with present invention. For those technologies or conditions not dichloromethane; stirred under ice-bath, the water phase was specifically described in the examples, they were performed acidified with concentrated hydrochloric acid then acidified according to the technologies or conditions as described in with acetic acid to reach pH=5-6, a solid was precipitated, the documents in the art or according to the product specifi 50 suction filtered, dried to obtain 2-(4-methoxyphenyl)-7-me cations. For those reagents and instruments whose manufac thylimidazol-2-a-pyridine-3-acetic acid (V) as yellowish turers were not given, they were all conventional products solid powder, 9.03 g, yield 51%. m.p. 234-236° C. (decom commercially available in markets. position), "H NMR(DMSO-de, 400 MHz)ö: 2.47(s.3H), 3.83 The synthesis of important intermediates involved in the (s, 3H), 4.14(s, 2H), 7.10(d. 1H, J–7.00 Hz), 7.12-7.14(m, present invention is illustrated in Examples 1-12. 55 2H), 7.54(s, 1H), 7.65-7.67(m, 2H), 8.53(d. 1H, J=7.00 Hz), 13.14(s, 1H). Example 1 Examples 2-6 Synthesis of 2-arylimidazol-2-a-pyridine-3-acetic acid (V) 60 Synthesis of Compounds V-V. a) 2-(4-methoxyphenyl)-7-methylimidazol-2-alpyridine In Examples 2-6, by referring to the method of Example 1 (II): 15.02 g (0.1 mol) of 4-methoxyphenylethylketone was for synthesizing Compound V, the following Compounds dissolved in 50 mL of methanol, added with 0.7 g (0.005 mol) V-V were synthesized. of anhydrous aluminum trichloride, stirred in ice-water bath, 65 2-(4-chlorophenyl)-7-methylimidazo[1,2-a-pyridine-3- added dropwise with 16.16 g (5.2 mL, 0.101 mol) of liquid acetic acid (V): light yellow solid powder, yield 20%. m.p. bromine, (color immediately faded, white solid was precipi 229-231° C., "H NMR(DMSO-de, 400 MHz)8: 2.42(s, 3H), US 8,980,887 B2 31 32 4.17(s, 2H), 7.06(d. 1H, J=7.00 Hz), 7.53(s, 1H), 7.57-7.62 influence the following condensation to form amide, so that (m. 2H), 7.76-7.78(m, 2H), 8.48(d. 1H, J–7.00 Hz), 12.96(s, they could be directly used in the next synthesis. 1H). The following Examples 13-40 were examples for synthe 2-(4-methylphenyl)-7-methylimidazo[1,2-alpyridine-3- sis of Compounds 1-28 of the present invention. acetic acid (V): white solid powder, yield 61.6%. m.p. 220 5 224°C. (decomposition), H NMR(DMSO-de, 400 MHz) 8: Example 13 2.35(s.3H), 2.38(s.3H), 4.08(s, 2H), 6.80(d. 1H, J–7.00 Hz), 7.27-7.29(m, 2H), 7.36(s, 1H), 7.63-7.65(m, 2H), 8.26(d. 1H, Synthesis of N-benzyl-N-ethyl-2-(4-chlorophenyl)- J=7.00 Hz). 7-methylimidazo 1,2-alpyridine-3-acetamide (Com 2-(3,4-dichlorophenylethylketone)-7-methylimidazo 1,2- 10 pound 1) apyridine -3-acetic acid (V): light yellow solid powder, yield 63.8%. m.p. 238-240° C., ESI-MS m/z:335|M+H", "H 0.9 g (0.003 mol) of 2-(4-chlorophenyl)-7-methylimidazo NMR(DMSO-de, 400 MHz)8: 2.38(s.3H), 4.15(s, 2H), 6.85 1.2-a-pyridine-3-acetic acid and 0.6 g (0.0045 mol) of (d. 1H, J=7.00 Hz), 7.39(s, 1H), 7.75(s, 2H), 7.98(s, 1H), 15 N-benzylethylamine were weighed, added to 80 mL of dry 8.31(d. 1H, J=7.00 Hz), 12.85(s, 1H). dichloromethane, then added with 1.0 g (0.005 mol) of EDC 2-(4-methylphenyl)-6-methylimidazo[1,2-alpyridine-3- hydrochloride. Stirred at room temperature and reacted for 24 acetic acid (Vs): white solid powder, yield 85.3%. m.p. 237 h, stopped the reaction until almost completion of the reac 239°C. (decomposition), ESI-MS m/z. 281M+H", "HNMR tion. Filtered to remove solid urea, concentrated, and then (DMSO-de, 400 MHz)ö: 2.33(s, 3H), 2.35(s, 3H), 4.09(s, separated with silica gel column chromatograph to obtain a 2H), 7.14(d. 1H, J=9.24 Hz), 7.27-7.29 (m, 2H), 7.50(d. 1H, crude product which was recrystallized with acetone to obtain J=9.24 Hz), 7.62-7.64(m, 2H), 8.21 (s, 1H), 12.74(s, 1H). a pure white solid powder, 0.5g in total, yield 39.9%. m.p. 2-(4-chlorophenyl)-6-methylimidazo[1,2-alpyridine-3- 192-193° C., ESI-MS m/z. 419 M+H", "H NMR (CDC1, acetic acid (V): light yellow solid powder, yield 18.5%. H 400 MHz)8: 1.20(t, 3H, J–7.00 Hz), 2.54(s, 1.7H), 2.56(s, NMR (DMSO-de, 400MHz)8: 2.33(s.3H), 4.12(s, 2H), 7.17 25 1.3H), 3.38(q, 0.8H, J=7.00 Hz), 3.57(q, 1.2H, J=7.00 Hz), 7.19(m. 1H), 7.52-7.53(m, 1H), 7.54-7.56(m, 2H), 7.75-7.78 4.11(s, 1H), 4.21(s, 1H), 4.59(s, 0.7H), 4.62(s, 1.3H), 7.09 (m. 2H), 8.24(s, 1H), 12.86(s, 1H). 7.15(m, 2H), 7.24-7.37(m, 5H), 7.46-7.56(m, 2H), 7.69-7.71 (m. 1H), 8.09-8.23(m, 2H). Example 7 30 Example 14 Synthesis of N-(arylmethyl)ethylamine N-ethyl-N-(2-pyridinylmethyl)-2-(4-chlorophenyl)- N-(4-pyridinylmethyl)ethylamine (VI): 15.70 g (0.147 7-methylimidazol-2-alpyridine-3-acetamide.hydro mol) of 4-pyridine-formaldehyde was dissolved in 200 mL of chloride (Compound 2) ethanol, added under stirring in cold-water-bath with 21 g 35 (0.296 mol) of 65-70% ethylamine aqueous solution, reacted According to the method of Example 13, 2-(4-chlorophe for 0.5 h, monitored with TLC until the reaction was almost nyl)-7-methylimidazol-2-alpyridine-3-acetic acid and completed. Added carefully with 5.6 g (0.148 mol) of sodium N-(2-pyridinylmethyl)ethylamine were used as raw materials borohydride in several batches, small amount in each batch, for synthesis, salified with hydrochloric acid-ethyl ether solu after the end of addition, added with 30 mL of water, reacted 40 overnight (20 h), the reaction was completed according to tion in dry dichloromethane, then crystallized with methanol TLC monitoring. Evaporated to remove solvent, added with tetrahydrofuranto obtain a corresopnding hydrochloride pure water, extracted with dichloromethane, washed with water product. Yellow solid powder, yield 51.2%. m.p. 178-180°C., and saturated Saline in order, dried with anhydrous sodium ESI-MS m/z: 420M+H", "H NMR(DO, 400 MHz)8: 0.95 sulfate, evaporated to remove solvent to obtain yellow thick 45 (t, 0.5H, J=7.00 Hz), 1.14(t, 2.5H, J=7.00 Hz), 2.38(s, 2.5H), liquid, 30 g, crude yield 73.4%. "H NMR(CDC1, 400 MHz) 2.40(s, 0.5H), 3.30(q, 0.4H, J=7.00 Hz), 3.56(q, 1.6H, J=7.00 8: 1.14(t, 3H, J–7.00 Hz), 2.66(q, 2H, J=7.00 Hz), 3.81 (s, HZ), 4.14(s, 0.4H), 4.36(s, 1.6H), 4.76(s, 1.6H), 4.86(s. 2H), 7.26-7.27(m, 2H), 8.52-8.54(m, 2H). 0.4H), 7.14-7.24(m, 1H), 7.30-7.46(m, 4H), 7.50(s, 1H), 7.69-7.75(m, 2H), 8.11-8. 13(m, 1H), 8.33-8.53(m, 2H). Examples 8-12 50 Example 15 Synthesis of Compounds VI-VI N-ethyl-N-(3-pyridinylmethyl)-2-(4-chlorophenyl)- In Examples 8-12, referring to the method of Example 7 for 7-methylimidazol-2-alpyridine-3-acetamide.hydro synthesizing Compound VI, the following Compounds VI 55 chloride (Compound 3) VI were synthesized, respectively. N-benzylethylamine (VI): 12.4g, crude yield 92%; According to the method of Example 14, 2-(4-chlorophe N-(3-pyridinylmethyl)ethylamine (VI): 47 g, crude yield nyl)-7-methylimidazol-2-alpyridine-3-acetic acid and 96%: N-(3-pyridinylmethyl)ethylamine were used as raw materials N-(2-pyridinylmethyl)ethylamine (VI): 19 g, crude yield 60 for synthesis, to obtain light yellow solid powder, yield 46.6%; 69.5%. m.p. 236-238° C., ESI-MS m/z: 420M+H", "H N-(2-pyridinylmethyl)-2-methoxyethylamine (VI): NMR(DO, 400 MHz)8: 0.95(t, 0.7H, J=7.00 Hz), 1.11(t, 13.17 g, crude yield 79.3%; 2.3H, J=7.00 Hz), 2.39(s, 2.3H), 2.40(s, 0.7H), 3.27(q, 0.5H, N-(3-pyridinylmethyl)-2-methoxyethylamine (VI): 16 g. J-7.00 Hz), 3.48(q, 1.5H, J=7.00 Hz), 4.13(s, 0.5H), 4.32(s, crude yield 97%. 65 1.5H), 4.60(s, 1.5H), 4.71(s, 0.5H), 7.15-7.22(m, 1H), 7.32 TLC showed that the above products contained a small 7.44(m, 4H), 7.51(s, 1H), 7.84(m. 1H), 8.12-8.14(m, 1H), amount of tertiary amine as by-product, but which did not 8.26(m, 1H), 8.52-8.53(m, 2H).

US 8,980,887 B2 39 40 Example 38 Instruments: high speed refrigerated centrifuge (H1ACH1 20PR-5), ultraspeed refrigerated centrifuge (H1ACH1 N-(2-methoxyethyl)-N-(2-morpholinylethyl)-2-(4- SCP85H), homogenizer (ULTRA-TURRAXT25), UV-250 methylphenyl)-6-methylimidazo[1,2-alpyridine-3- ultraviolet spectrophotometer (Shimadzu Company, Japan), acetamide.hydrochloride (Compound 26) 5 multihead suction filter (self-made), LS6500 type scintilla tion counter (Beckman Company), 49 type glass fiber filter According to the method of Example 14, 2-(4-methylphe membrane (Shanghai Yuguang Scavenging Material Inte nyl)-6-methylimidazol-2-alpyridine-3-acetic acid and grated Corporation) N-(2-methoxyethyl)-2-morpholine-ethylamine were used as Reagents: H-PK1 1195(5 uCi (83.4Ci/mmol)) and scintil raw materials for synthesis, to obtain white solid powder, 10 lation solution were purchased from PE company, PK1 1195, yield 34.2%. m.p. 245-247° C., ESI-MS m/z.: 451 M+H", R05-4864, Polyethyleneimine (PEI), bovine serum albumin H NMR(DMSO-de, 400 MHz)8: 2.41(s, 3H), 2.48(s, 3H), (BSA), protease inhibitor (PMSF) were purchased from 3.05-3.10(m, 2H), 3.25(s, 3H), 3.36-3.38(m, 2H), 3.55-3.60 Sigma Company, Folin-phenol reagent was purchased from (m, 4H), 3.69(m,2H), 3.80(m,2H), 3.95(m, 4H), 4.58(s, 2H), 15 Huaweikeyi Company, Tris-HCl Buffer pH7.4(50 mM Tris 7.44-7.53(m, 4H), 7.87-7.90(m, 2H), 9.46(s, 1H). HC1 Buffer, 1 mM EDTA, 5 mM MgCl, 1 mM PMSF, 0.1% NaNs, 3 g/mL protease inhibitor), other reagents were all Example 39 analytically pure (Beijing Chemical Reagents Company). Test drugs: Compounds 1-28(see: Table 1), total 28 com N-ethyl-N-(4-pyridinylmethyl)-2-(4-methylphenyl)- pounds 6-methylimidazol-2-alpyridine-3-acetamide.hydro Experimental Methods: chloride (Compound 27) 1) Preparation of Rat Heart TSPO Membrane Protein: According to the method of Example 14, 2-(4-methylphe Wister rats, 220-260 g, female and male, were sacrificed by nyl)-6-methylimidazol-2-alpyridine-3-acetic acid and decapitation and the ratheart were rapidly separated, weighed N-(4-pyridinylmethyl)ethylamine were used as raw materials 25 and to which homogenized in 10 times volume of Tris-HCl for synthesis, to obtain light yellow solid powder, yield buffer solution (50 mM Tris-HCl, 5 mM MgCl, 1 mM 78.9%. m.p. 222-224° C., ESI-MS m/z: 399|M+H", "H EDTA, 0.5% (W/V) BSA, 1 mM PMSF, 3 g/ml proteinase NMR(DMSO-de, 400 MHz)8: 1.11(t, 0.7H, J=7.00 Hz), 1.24 inhibitor, 0.1% NaN, 0.32M sucrose, pH 7.4) at 15,000 rpm (t, 2.3H, J–7.00 Hz), 2.41(s, 0.7H), 2.43(s, 2.3H), 2.46(s, for 30s, total 5 times. The homogenate was centrifuged under 30 1000xg for 10 minutes and the supernatant was then centri 2.3H), 2.47(s, 0.7H), 3.43(q, 0.5H, J=7.00 Hz), 3.63(q, 1.5H, fuged under 30000xg for 20 minutes. The precipitate was J=7.00 Hz), 4.24(s, 0.5H), 4.56(s, 1.5H), 4.78(s, 1.5H), 5.02 collected, and resuspended with 10 times Volume of Tris-HCl (s, 0.5H), 7.39-7.43(m. 1H), 747-7.55(m, 4H), 7.85-7.89(m, buffer solution (pH 7.4) relative to the original weight, then 2H), 7.91-7.93(m. 1H), 8.75(s, 1H), 8.80-8.83 (m, 2H). centrifuged under 30000xg for 20 minutes. The precipitate Example 40 35 was washed with the same buffer solution, centrifuged under 30000xg for 20 minutes and the precipitate was suspended N-ethyl-N-(4-pyridinylmethyl)-2-(4-chlorophenyl)- with the above buffer solution. After sub-packaged (the whole 6-methylimidazol-2-alpyridine-3-acetamide.hydro operation procedures were performed under ice bath), the chloride (Compound 28) product was stored at -80° C. 40 2) Measurement of Protein Content (Folin Method) According to the method of Example 14, 2-(4-chlorophe 100LL of sample, which contained BSA 5-100 g (used for nyl)-6-methylimidazol-2-alpyridine-3-acetic acid and making standard curve) or a sample to be tested, and comple N-(4-pyridinylmethyl)ethylamine were used as raw materials mented with water when less than 100 uL, was added to 100 uL with reagent A ((1) 0.2N NaOH solution containing 4% for synthesis, to obtain white solid powder, yield 32.9%. m.p. sodium carbonate and 0.2% sodium tartrate 229-231°C., ESI-MS m/z. 420M+H", "HNMR(DMSO-d 45 400 MHz)8: 1.11(t, 0.6H, J=7.00 Hz), 1.25(t, 2.4H, J=7.00 (NaCHO.2H2O), (2) 4% copper sulfate (CuSO4.5H2O) Hz), 2.47(s, 2.4H), 2.49(s, 0.6H), 3.42(q, 0.4H, J=7.00 Hz), water Solution, homogeneously mixing (1) and (2) in propor 3.63(q, 1.6H,J-7.00Hz), 4.25(s, 0.4H), 4.56(s, 1.6H), 4.78(s, tion of 100:1 to obtain the reagent A, which should be used 1.6H), 5.01(s, 0.4H), 7.55-7.58(m, 1H), 7.65-7.76(m, 4H), within one day after being prepared), mixed and reacted at 50 room temperature for 10 min, then added with 20 uL reagent 7.84-7.86(m, 2H), 7.90-7.92(m. 1H), 8.71(s, 1H), 8.80-8.84 B (Folin phenol reagent, final concentration: 1N), mixed (m. 2H). immediately, placed in 50° C. water bath, incubated for 15 Example 41 min, 200 uL of the mixture was taken and measured to deter mine optical density value using trace multichannel scanning Screening of Drugs Using Translocation Protein 55 optical densitometer, wavelength 690 nm, optical path 0.6 (TSPO, 18KD) and Radioligand (H-PK1 1195) cm, and 100 uL of HO was used as blank control to replace Binding Test Model the sample. 3) Competitive Binding Test of Drug to the Receptor (Rat Experimental Mechanism: Heart TSPO) and Radioligand (H-PK1 1195): In the present test, TSPO protein separated and purified 60 from rat heart was used as screening target, via competitive binding test with radioligand (H-PK1 1195), to screen TSPO Total Non-specific ligand compounds. binding tube Test tube binding tube Experimental Materials: Animals: Wister rats (220-260 g, male and female), pur 65 chased from the Laboratory Animal Center of the Academy of Military Medical Sciences. US 8,980,887 B2 41 42 (1) tubes were placed in reaction condition of 30°C. 9 gradient concentrations in 10-10M, and their ICso and (2) all tubes were added with 20 g of receptor protein in K values were calculated by plotting and fitting. The results order; are shown in Table 3. (3) the test tubes were added in order with 20 uL of drugs in certain concentrations; 5 TABLE 3 (4) the non-specific binding tubes were added with 20LL of non-tagged ligand (PK1 1195), the final concentration of the The activities of some active compounds to the non-tagged ligand was 0.1 mM, pre-reacted for 30 min; separated and purified TSPO (5) all tubes were added in order with 25 uLH-PK1 1195, Compound ICso (nM) K(nM) 10 the final concentration of the labeled ligand was 1.5 nM; Rio 5-4864 O.68 O.29 (6) Tris-HCl Buffer pH7.4 was used to complement the Compound 1 16.86 7.17 reaction volumes of all tubes to reach 200 uL.; Compound 7 115.60 49.19 (7) the reaction was performed under 30° C. reaction con Compound 8 21.94 9.34 dition for 1 h; Compound 10 26.OS 11.09 15 Compound 11 1564 6.66 (8) Then samples were applied to 49-type glass fibre filter, Compound 13 6.99 2.97 vacuum suction filtered, then washed with 2 ml ice-cold Tris Compound 14 91.02 38.73 HCl buffer solution (50 mM Tris-HCl buffer solution, 1 mM EDTA, 5 mM MgCl, 1 mM PMSF, 0.1% NaN, 3 g/ml proteinase inhibitor, pH 7.4). The filter was dried and placed Below Examples 42-47 are animal behavior tests, includ in a scintillation vial with 1 ml of scintillation fluid. The ing: mice open field spontaneous locomotor activity test, radio-activity was measured by a Scintillation counter. mice tail Suspension test, mice elevated plus maze test, and rat Experimental Results: forced Swim test. (1) The TSPO separated and purified from rat heart was Animals: ICR mice (source: Beijing Vital Laboratory Ani used as drug-screening target, via the binding test with radio mal Technology Company), male, body weight 20-24 g; SD ligand (H-PK1 1195), 29 compounds were screened, in 25 rats (Source: Beijing Vital Laboratory Animal Technology which Ro5-4864 was used as positive control, and the 29 Company), male, SPF grade, body weight 180-220g. compounds were subjected to competitive binding test Drugs: Compound 8(8", YL-IPAO8), Compound 10(10", respectively. The screening results show that in comparison YL-IPA10), Compound 11(11", YL-IPA11) and Compound with the positive control, the screened compounds have com 13(13", YL-IPA13), Diazepam (DZP), Desipramine (DMI); petitive binding results as shown in Table 2: 30 administration manner: oral administration (po); intraperito neal administration (ip). TABLE 2 Statistic methods: All data were expressed as mean+SEM. Except that PK1 1195 antagonism test was determined by Screening results of TSPO ligand compounds (n = 6 times two-way analysis of variance, all other tests were determined 35 by one-way analysis of variance, and Bonferroni test was Inhibition rate (% used for group comparison. Compound 1 x 10M 1 x 107M 1 x 10M Example 42 ROS-4864 100 82 57 (positive control) 40 Mice Spontaneous Locomotor Activity in Mice Compound 1 100 87 12 Compound 2 100 59 O Compound 3 100 25 O Experimental mechanism: the aim was to observe the Compound 4 100 50 O effects of drugs on central nervous excitation, so as to exclude Compound 5 100 43 O false positive reactions of anxiolytic or antidepressant effects Compound 6 70 O O 45 caused by central nervous excitation. After administration, Compound 7 99 72 10 Compound 8 100 89 30 apparent central nervous excitation or inhibition effects were Compound 9 86 8 O observed, when the observed indexes were equivalent to those Compound 10 100 85 23 of the blank control group, there were not apparent central Compound 11 100 65 29 nervous excitation or inhibition effects; when the observed Compound 12 8O 2O O 50 Compound 13 97 89 42 indexes were significantly higher than those of the blank Compound 14 97 66 14 control, there were apparent central nervous excitation Compound 15 90 15 O effects, on the contrary, there were central nervous inhibition Compound 16 72 41 O effects. Compound 17 83 9 O Compound 18 69 32 O 1) Experimental device: the mice open field box was a Compound 19 94 76 O 55 colorless transparent organic glass box (30x36x25 cm). Compound 20 61 63 O which bottom surface was divided into 9 lattices. Compound 21 43 11 O 2) Experimental operation: Compound 8(8", YL-IPAO8), Compound 22 63 9 4 Compound 23 85 2 3 Compound 10(10", YL-IPA10), Compound 11(11", Compound 24 17 3 O YL-IPA11) and Compound 13(13", YL-IPA13) (separately Compound 25 31 O O 60 having three dose groups of 0.03, 0.3, 3 mg/kg) and blank Compound 26 48 1 O control (distilled water, DW) were administered intragastri Compound 27 91 65 O cally, and the test started after 55 min. During test, the mice Compound 28 84 33 O were placed in the central area of the open field spontaneous locomotor activity observation box, started timing immedi Compounds 1, 7, 8, 10, 11, 13 and 14 that had higher 65 ately, the spontaneous activities of mice within 5 min were binding activity as shown in the above screening test were recorded artificially (observation indexes: number of rear further subjected to radioligand competitive binding test with ings, number of crossings). US 8,980,887 B2 43 44 3) Experimental results: as shown in FIG. 1 and FIG. 2. group was administered by intraperitoneal injection with The above two indexes of Compound 8 and 10, in doses of PK1 1195 simultaneously when Compound 8 was intragastri 0.03, 0.3, 3 mg/kg, were equivalent to those of the control, ally administered. which showed Compound 8 and 10 did not have apparent Statistic method: the results were expressed in central nervous excitation or inhibition effects; meant-SEM. The result was determined by two-way analysis Compound 11 was equivalent to the control in the two of variance, and Bonferroni test was used for group compari indexes only when the dose was 3 mg/kg, and was lower than SO. the control when the dose was 0.03 and 0.3 mg/kg, which The results were shown in FIG. 4, in comparison with the Suggested it could have central nervous inhibition effects; control, single administration of TSPO selective antagonist Compound 13 was apparently lower than the control (DW) 10 PK11 195(3 mg/kg, ip) had no significant influence on immo when the dose was 0.03, 0.3, 3 mg/kg, and the activity bility time in mice tail Suspension test, while in comparison declined with the increase of dose, which Suggested that it had with the group with single administration of YL-IPA08(0.1 certain central nervous inhibition effects. mg/kg), the PK1 1195+YL-IPAO8 group increased the immo bility time (P<0.05), which suggested that the antidepressant Example 43 15 effect of YL-IPAO8 could be antagonized by TSPO antagonist PK1 1195 in mice tail suspension test. Mice Tail Suspension Test Example 45 Experimental mechanism: mice tail Suspension test was an acute behavioral despair model established by Steru et al Mice Elevated Plus Maze Test (1985). In this model, mice struggled at full stretch to escape discomfort posture, and the motionless state intermittently Experimental mechanism: In this test, animals were placed appeared due to invalid struggle was deemed as "despair in the central area of maze, then the time and number the state', while typical antidepressant (such as tricyclics, SSRI) animals separately entered open arm and close arm within a all could significantly reduce mice immobility time. This 25 certain time period were observed. Since this has certain model was easy in operation, with good predictability, and novelty and certain threatening for the animal, the animals was the most popular model for screening antidepressants. would generate curiosity and anxiety reaction. When having 1) Experimental device: an experimental frame with spac high anxiety level, the animals would leave the open arm and ing boards which dividing the experimental frame into 2 stayed in the close arm, otherwise the animals would stay in experimental chambers (25x25x35 cm). A clamp is mounted 30 the open arm for more time with increased number of explor on a through cross rod in the chamber. ing open arm. Typical anxiolytic drugs (such as benzodiaz 2) Experimental Methods epines) can selectively increase the animals behavior of Male Kunming mice weighing 20-25 g. The mice were exploring open arm without influencing total number and intragastrically administered with Compound 8, vehicle (dis total time of entering arms. tilled water, DW) or positive control drug (desipramine, 35 1) Experimental device: mice elevated plus maze was a DMI). After 1 h, wrap adhesive tape around the mouse's tail cross shape colorless transparent organic glass box, arm three quarters of the distance from the base of the tail and then length 30 cm, width 5 cm, the close arm had sides surrounded Suspend the animals by passing the Suspension hook through with side wall with height of 15 cm, and opened top; the open the adhesive tape 5 cm above the table. The duration of arm was total open; the joint area (central area) for the open immobility in the last 4 min of total 6 mintest was recorded. 40 and close arms was 5x5 cm. The total device was elevated Compound 8 was dissolved in distilled water, had doses of with a distance of 45 cm from the ground. 0.1, 0.3, 1 mg/kg, respectively, and administration in a Vol 2) Experimental operation: male Kunming mice, body ume of 10 mL/kg, desipramine had dose of 30 mg/kg was the weight 20-25 g, were separately administered intragastrically minimum effective dose to generate antidepression activity of with Compound 8 or the blank control distilled water (DW) desipramine, which was the minimum effective dose to gen 45 and observed after 1 h, or administered intraperitoneally with erate antidepression activity. positive control drug diazepam (DZP) and observed after 30 Statistic method: All data were expressed as meant-SEM. min. During observation, place the animal in the central plat The results were determined by one-way analysis of variance, form, facing an open arm. Observe the animal for 5 min. The and Bonferroni test was used for group comparison. numbers of entries into open arms and closed arms as well as 3) Experimental results, as shown in FIG. 3. 50 the time spent in open arms or closed arms were recorded. It can be seen in FIG. 3, the mice with intragastric admin Compound 8(8i, YL-IPA08) was separately at three doses istration of Compound 8 exhibited antidepression activity of 0.1.0.3, 1 mg/kg, and 2 mg/kg was the minimum effective superior to the positive control desipramine (DMI) in tail dose for generating anxiolytic-like effects of diazepam. Suspension test, and the relation between potency and dose Observation indexes: percentage of number of entering was in reverse U type distribution. 55 open arm number of entering arms/(number of entering open arm--number of entering close arm) Example 44 Percentage of time spent in open arm time spent in open arm? (time spent in open arm--time spent in close arm) Blocking Effects of TSPO Antagonist PK11195 on Observation indexes: entering open and close arms refers Compound 8(YL-IPAO8) Antidepressant Activity 60 to all four paws entering the arms. Experimental results: the result of Compound 8 was shown The optimum dose (0.1 mg/kg) of YL-IPA08 in antidepres in FIG. 5. Compound 10 (10H, YL-IPA10), Compound 11 sant effect of mice in tail Suspension model was used to (11+, YL-IPA11) and Compound 13 (13i, YL-IPA13) were perform drug antagonism test, and the method was identical subjected to the same test, and the results were shown in FIG. to that of Example 43, except that PK1 1195 group and 65 6, FIG. 7. PK1 1195+Compound 8 antagonism group with single intra It can be seen from the figures that in the mice elevated plus peritoneal injection (ip) were added, wherein the antagonism maze test, the intragastric administration of Compound 8 at US 8,980,887 B2 45 46 doses of 0.1.0.3, 1 mg/kg could relatively increase the num rat serum PREG and PROG were separately measured using ber and time the mice spent entering in open arm, and did not ELISA or radio-immunoassay kit. influence the total number and total time the mice entering The measurement of PREG used ELISA kit from German open arm and close arm. In comparison with the blank control DRG distilled water (DW) group, the 0.3 mg/kg group showed Company, and the operation was performed according to significant difference in the percentage of number of entering its specification. The measurement of PROG used 'I-PROG open arm and the percentage of time spent in open arm, which radio-immunoassay kit from Beijing Beifang Biological Sci Suggested that Compound 8 had significant anxiolytic effects ence and Technology Institute, and the operation was per at dose of 0.3 mg/kg. formed according to its specification. Compound 10, was equivalent to the control at dose of 10 Statistic methods: the results were expressed in average 0.03, 0.3 mg/kg, while significant higher than the control at value itstandard error, one-way analysis of variance was used dose of 3 mg/kg. This suggested that Compound 10 had for the test results, and Bonferroni test was used for group significant anxiolytic effects, and its anxiolytic onset dose comparison. was higher than that of Compound 8. Experimental results: the results showed that after the Compound 11, was only equivalent to the control in the 15 administration (p.o.) of YL-IPA08 for 60 min, the contents of percentage of number of entering open arm at dose of 0.03 rat serum PREG and PROG increased in dose-dependent mg/kg, and was significantly lower in indexes at other doses manner, in comparison with the blank control group, signifi in comparison with the control, which Suggested that Com cant differences were observed in doses of 3 mg/kg and 10 pound 11 had no significant anxiolytic effects in this model. mg/kg, and the results were shown in FIG. 9, FIG. 10. This Compound 13, was significantly lower than the control in suggested that the antiadepression behavior effects of YL all indexes at dose of 0.03, 0.3.3 mg/kg, which suggested that IPAO8 could be related to the increase of neurosteroid in vivo. Compound 13 had no significant anxiolytic effects in this Although the present invention is described in details in the model. specific examples, those skilled in the art would understand those details could be modified or replaced under the teach Example 46 25 ings as disclosed, and all of these modifications fall within to the protection scope of the present invention. The protection Rat Forced Swim Test scope of the present invention was determined by the attached claims and any equivalents thereof. The method established by Porsolt Eur J. Pharmacol. 1978, 47(4): 379-91.) was used, in which rat Swim tank was a 30 What is claimed is: round glass with height of 40 cm, diameter of 20 cm, and 1. A compound of Formula I, its tautomer, its racemic or water depth of 25 cm, the water temperature was 28°C. 24h optical isomer, its pharmaceutically acceptable salt (which is before the test, the rats one-by-one were placed in the swim water soluble), or its solvate, tank, Swam 15 min in advance, then dried and put back in the original rearing cage. 60 min before the test, they were sepa 35 rately administered (p.o.) with YL-IPAO8, DLX or DW at different doses. During the test, the rats were placed again in the Swim tank, and timing and observation started and con tinued for 5 min, the accumulated immobility time was recorded using stopwatch. The standard for judging motion 40 less was that animal stopped struggle in water and was in floating state, or had little limb motion to keep head float. Statistic method: the results were expressed in meant-SEM. The result was determined by one-way analysis YR of variance, and Bonferroni test was used for group compari 45 SO. Experimental results: in comparison with the blank con wherein: trol, YL-IPAO8(1,3, 10 mg kg) showed increased immobil R" is selected from ethyl, propyl, butyl, and methoxyethyl: ity time significantly shortened Swim immobility time (all R’ is selected from 2-pyridinylmethyl, 3-pyridinylmethyl, had P<0.05) (FIG. 8), and was equivalent to the positive drug 50 4-pyridinylmethyl, 2-morpholinylethyl, and 3-mor DMI (40 mgkg'). This suggested that YL-IPAO8 had anti pholinylpropyl; depressant effect in this model. The results are shown in FIG. R is 6-methyl or 7-methyl: 8. R" is 1-3 substituents selected from H, halogen, alkyl, substituted hydrocarbonyl, alkenyl, substituted alkenyl, Example 47 55 phenyl, substituted phenyl, heteroaryl, substituted het eroaryl, C-C alkoxyl, Cs-Co aryloxy, Substituted ary Measurement of Contents of Rat Serum loxy, C-C alkylamino, Cs-C arylamino, Substituted Neurosteroid Pregnenolone (PREG) and arylamino, di-(C-C alkyl)amino, di-(Cs-Co aryl) Progesterone (PROG) amino, di-(Substituted aryl)amino, Cohydrocarbony 60 lacyloxy, Cao arylacyloxy, Co hydrocarbonylacy 24 male SD rats were randomly divided into 4 groups, lamino, Cao arylacylamino, carboxyl, Co separately being YL-IPAO8(1, 3, 10 mg/kg) groups and dis hydrocarbonyloxyformyl, Co aryloxyformyl, amino tilled water (DW) group, were immediately sacrificed by formyl, Cohydrocarbonylaminoformyl, or Cary decapitation after the end of rat forced swim test (same as the laminoformyl; wherein the heteroaromatic cycle is a method of Example 46), their trunk blood samples were 65 monocyclic or fused aromatic hydrocarbonyl having 1-3 taken, stood at room temperature for 3 h, centrifuged (3000 heteroatoms selected from N, O or S, each of the sub rpm, 20 min) to take serum, stored at -20°C. The contents of stituents of groups having Substituents is selected from US 8,980,887 B2 47 48 halogen, hydroxyl, cyano, nitro, Calkyl, Calkoxyl, -position of imidazo[1,2-alpyridine ring; R is at ortho-, C. alkylthio, mono- or di- or tri-halogenated C. meta- or para-position of benzene ring. alkyl, amino, Ce alkylamino, Cohydrocarbonylacy 7. The compound of Formula I according to claim 6, its loxy, Cohydrocarbonylacylamino, Cao arylacyloxy, tautomer, its racemic or optical isomer, its pharmaceutically and Co arylacylamino. acceptable salt, or its solvate, wherein, R and Rare inde 2. The compound of Formula I according to claim 1, its pendently selected from F, Cl, Br, I, C-C alkyl, C-C, tautomer, its racemic or optical isomer, its pharmaceutically alkoxylethyl, and C-C alkoxyl, wherein Rhas 1-2 substitu acceptable salt, or its solvate, wherein R is at 4-, 5-, 6-, or ents, and R has 1-3 substituents. 7-position of imidazo[1,2-alpyridine ring; R is at ortho-, 8. The compound of Formula I according to claim 6, its meta- or para-position of benzene ring. 10 tautomer, its racemic or optical isomer, its pharmaceutically 3. The compound of Formula I according to claim 1, its acceptable salt, or its solvate, wherein R' is ethyl or meth tautomer, its racemic or optical isomer, its pharmaceutically oxyethyl. acceptable salt, or its solvate, wherein, Rand R are inde 9. A compound, its tautomer, its racemic or optical isomer, pendently selected from F, Cl, Br, I, C-C alkyl, C-C, its pharmaceutically acceptable salt, or its Solvate, which is alkoxylethyl, and C-C alkoxyl, wherein Rhas 1-2 substitu 15 selected from the following compounds: ents, and R has 1-3 substituents. N-benzyl-N-ethyl-2-(4-chlorophenyl)-7-methylimidazo 4. The compound of Formula I according to claim 1, its 1.2-alpyridine-3-acetamide; tautomer, its racemic or optical isomer, its pharmaceutically N-ethyl-N-(2-pyridinylmethyl)-2-(4-chlorophenyl)-7-me acceptable salt, or its solvate, wherein R' is ethyl or meth thylimidazol-2-alpyridine-3-acetamide.hydrochlo oxyethyl. ride; 5. A compound of Formula I, its tautomer, its racemic or N-ethyl-N-(3-pyridinylmethyl)-2-(4-chlorophenyl)-7-me optical isomer, its pharmaceutically acceptable salt (which is thylimidazol-2-alpyridine-3-acetamide.hydrochlo water soluble), or its solvate, ride; 25 N-ethyl-N-(4-pyridinylmethyl)-2-(4-chlorophenyl)-7-me thylimidazol-2-alpyridine-3-acetamide.hydrochlo

ride; N-(2-methoxyethyl)-N-(2-pyridinylmethyl)-2-(4-chlo rophenyl)-7-methylimidazol-2-alpyridine-3-acetami 30 dehydrochloride; N-(2-methoxyethyl)-N-(3-pyridinylmethyl)-2-(4-meth ylphenyl)-7-methylimidazol-2-alpyridine-3-acetami dehydrochloride; N-benzyl-N-ethyl-2-(3,4-dichlorophenyl)-7-methylimi 35 dazol-2-alpyridine-3-acetamide; YR N-ethyl-N-(2-pyridinylmethyl)-2-(3,4-dichlorophenyl)-7- methylimidazol-2-alpyridine-3-acetamide.hydrochlo wherein: ride; R" is selected from ethyl, propyl, butyl, and methoxyethyl: N-ethyl-N-(3-pyridinylmethyl)-2-(3,4-dichlorophenyl)-7- R is selected from 2-pyridinylmethyl, 3-pyridinylmethyl, 40 methylimidazol-2-alpyridine-3-acetamide-hydrochlo ride; 4-pyridinylmethyl, 2-morpholinylethyl, and 3-mor N-ethyl-N-(4-pyridinylmethyl)-2-(3,4-dichlorophenyl)-7- pholinylpropyl; methylimidazol-2-alpyridine-3-acetamide-hydrochlo R is 1-2 substituents selected from H, halogen, alkyl, ride; substituted hydrocarbonyl, alkenyl, substituted alkenyl, 45 N-(2-methoxyethyl)-N-(2-pyridinylmethyl)-2-(3,4- phenyl, substituted phenyl, heteroaryl, substituted het dichlorophenyl)-7-methylimidazo 1,2-alpyridine-3-ac eroaryl, C-C alkoxyl, Cs-Co aryloxy, Substituted ary etamide-hydrochloride; loxy, C-C alkylamino, Cs-Co arylamino, Substituted N-(2-methoxyethyl)-N-(3-pyridinylmethyl)-2-(3,4- arylamino, di-(C-C alkyl)amino, di-(C-C aryl) dichlorophenyl)-7-methylimidazo 1,2-alpyridine-3-ac amino, di-(substituted aryl)amino, Cohydrocarbony 50 etamide.hydrochloride; lacyloxy, Co arylacyloxy, Co hydrocarbonylacy N-benzyl-N-ethyl-2-(4-methylphenyl)-7-methylimidazo lamino, Cao arylacylamino, carboxyl, Co 1.2-alpyridine-3-acetamide; hydrocarbonyloxy formyl, Co aryloxy formyl, amino N-ethyl-N-(2-pyridinylmethyl)-2-(4-methylphenyl)-7- formyl, Cohydrocarbonylaminoformyl, or Cary methylimidazol-2-alpyridine-3-acetamide.hydrochlo laminoformyl; wherein the heteroaromatic cycle is a 55 ride; monocyclic or fused aromatic hydrocarbonyl having 1-3 N-ethyl-N-(3-pyridinylmethyl)-2-(4-methylphenyl)-7- heteroatoms selected from N, O or S, each of the sub methylimidazol-2-alpyridine-3-acetamide.hydrochlo stituents of groups having Substituents is selected from ride; halogen, hydroxyl, cyano, nitro, Calkyl, Calkoxyl, N-ethyl-N-(4-pyridinylmethyl)-2-(4-methylphenyl)-7- C. alkylthio, mono- or di- or tri-halogenated C. 60 methylimidazol-2-alpyridine-3-acetamide.hydrochlo alkyl, amino, Calkylamino, Cohydrocarbonylacy ride; loxy, Cohydrocarbonylacylamino, Cao arylacyloxy, N-(2-methoxyethyl)-N-(2-pyridinylmethyl)-2-(4-meth and Co arylacylamino; and ylphenyl)-7-methylimidazol-2-alpyridine-3-acetami R" is 4-chloro, 3,4-dichloro, 4-methyl, or 4-methoxy. dehydrochloride; 6. The compound of Formula I according to claim 5, its 65 N-(2-methoxyethyl)-N-(3-pyridinylmethyl)-2-(4-meth tautomer, its racemic or optical isomer, its pharmaceutically ylphenyl)-7-methylimidazol-2-alpyridine-3-acetami acceptable salt, or its solvate, wherein, R is at 4-, 5-, 6-, or7 dehydrochloride; US 8,980,887 B2 49 N-benzyl-N-ethyl-2-(4-methoxyphenyl)-7-methylimi dazol-2-alpyridine-3-acetamide; VIII N-ethyl-N-(2-pyridinylmethyl)-2-(4-methoxyphenyl)-7- methylimidazol-2-alpyridine-3-acetamide.hydrochlo ride; 5 N-ethyl-N-(3-pyridinylmethyl)-2-(4-methoxyphenyl)-7- methylimidazol-2-alpyridine-3-acetamide-hydrochlo via Friedel–Crafts acetylation to form a ketone compound ride; of Formula VII: N-ethyl-N-(4-pyridinylmethyl)-2-(4-methoxyphenyl)-7- VII methylimidazol-2-alpyridine-3-acetamide.hydrochlo 10 O; ride; N-(2-methoxyethyl)-N-(2-pyridinylmethyl)-2-(4-meth oxyphenyl)-7-methylimidazol-2-alpyridine-3-aceta mide.hydrochloride; 15 b) reacting the ketone compound VII with bromine under N-(2-methoxyethyl)-N-(3-pyridinylmethyl)-2-(4-meth the catalysis of aluminum trichloride to form a bromide, oxyphenyl)-7-methylimidazol-2-alpyridine-3-aceta not being separated, reacting with an aminopyridine mide.hydrochloride; compound of Formula VI, N-(2-methoxyethyl)-N-(2-morpholinylethyl)-2-(4-meth VI ylphenyl)-7-methylimidazol-2-alpyridine-3-acetami dehydrochloride; N-(2-methoxyethyl)-N-(2-morpholinylethyl)-2-(4-meth ylphenyl)-6-methylimidazol-2-alpyridine-3-acetami dehydrochloride; under heating and in the presence of an alkali or alkaline N-ethyl-N-(4-pyridinylmethyl)-2-(4-methylphenyl)-6- 25 compound to form an imidazopyridine compound of methylimidazol-2-alpyridine-3-acetamide.hydrochlo Formula V: ride; and N-ethyl-N-(4-pyridinylmethyl)-2-(4-chlorophenyl)-6-me thylimidazol-2-alpyridine-3-acetamide.hydrochlo 30 ride. 10. A pharmaceutical composition comprising at least one compound of Formula I according to claim3, its tautomer, its racemic or optical isomer, its pharmaceutically acceptable C) reacting the imidazopyridine compound V with dim salt, or its solvate, and optionally a pharmaceutically accept 35 ethylamine and formaldehyde aqueous Soltuion in acetic acid to form a Mannich base, separating via filtration, able carrier or adjuvant. then reacting with iodomethane to form a quaternary 11. The compound of Formula I according to claim 3, its ammonium salt of Formula IV: racemic or optical isomer, its pharmaceutically acceptable salt, or its solvate, wherein R. Rare independently selected IV from F, Cl, methyl, ethyl, methoxyethyl, methoxy, and 40 ethoxy. 12. The compound of Formula I according to claim 3, its racemic or optical isomer, its pharmaceutically acceptable salt, or its solvate, wherein R is 2-pyridinylmethyl, 3-pyridi nylmethyl, 4-pyridinylmethyl, or 2-morpholinylethyl. 45 13. A pharmaceutical composition, comprising at least one compound of Formula I according to claim 7, its tautomer, its racemic or optical isomer, its pharmaceutically acceptable d) reacting the quaternary ammonium salt IV with a cya salt, or its solvate, and optionally a pharmaceutically accept 50 nide to form a corresponding nitrile, then hydrolyzing in able carrier or adjuvant. the presence of a strong base, and acidifying to form a 14. The compound of Formula I according to claim 7, its carboxylic compound of Formula II racemic or optical isomer, its pharmaceutically acceptable salt, or its solvate, wherein R. Rare independently selected II from F, Cl, methyl, ethyl, methoxyethyl, methoxy, and 55 ethoxy. 15. The compound of Formula I according to claim 7, its racemic or optical isomer, its pharmaceutically acceptable salt, or its solvate, wherein R is 2-pyridinylmethyl, 3-pyridi nylmethyl, 4-pyridinylmethyl, or 2-morpholinylethyl. 60 16. A method for preparing the compound of Formula I, its tautomer, its racemic or optical isomer, its pharmaceutically e) in the presence or absence of a catalyst, Such as 4-dim acceptable salt, or its Solvate according to claims 1, compris ethylaminopyridine, reacting the carboxylic compound ing the following steps: 65 of Formula II as obtained in step d) with an amine a) converting an aromatic hydrocarbon compound of For compound of Formula III in the presence of a condens mula VIII: ing agent: US 8,980,887 B2 51 52 b) Subjecting the above ketonic acid compound of Formula III VIII' to bromination with bromine to form abrominated acid compound of Formula VII': R2 1N R',1 5 VII to obtain a compound of Formula I O

I N OH:

10 R!-- 2 Br O c) reacting the above brominated acid compound of For mula VII' with a chloroformate (such as ethyl chlorofor mate or isobutyl chloroformate) to form a mixed acid 15 anhydride, then reacting with an amine of Formula III:

III wherein: -N R" is selected from ethyl, propyl, butyl, and methoxyethyl: R2 RI R’ is selected from 2-pyridinylmethyl, 3-pyridinylmethyl, 20 4-pyridinylmethyl, 2-morpholinylethyl, and 3-mor in the presence or absence of a catalyst, and in the presence pholinylpropyl; of an alkali to form a bromonated amide compound of R is 6-methyl or 7-methyl: Formula II': R" is 1-3 substituents selected from H, halogen, alkyl, Substituted hydrocarbonyl, alkenyl, Substituted alkenyl, 25 O RI II phenyl, substituted phenyl, heteroaryl, substituted het- M eroaryl, C-C alkoxyl, Cs-Co aryloxy, Substituted ary- N V loxy, C-C alkylamino, Cs-Co arylamino, Substituted R-1 R2; arylamino, di-(Cs-Co alkyl)amino, di-(Cs-Co aryl) 21 Br O amino, di-(substituted aryl)amino, C-C hydrocarbo- 30 nylacyloxy, Co-Co arylacyloxy, C-Cohydrocarbony- d) Subjecting the above bromonated amide compound of lacylamino, C-C arylacylamino, carboxyl, C-Co Formula I1" and an aminopyridine compound of For hydrocarbonyloxy formyl, Co-Co aryloxy formyl, ami- mula VI: noformyl, C-Co hydrocarbonylaminoformyl, or Co-Co arylaminoformyl; wherein the heteroaromatic 35 VI cycle is a monocyclic or fused aromatic hydrocarbonyl oy-R having 1-3 heteroatoms selected from N, O or S, each of HN \ / the Substituents of groups having Substituents is selected N from halogen, hydroxyl, cyano, nitro, C-C alkyl, C-C alkoxyl, C-C alkylthio, mono- or di- or tri-ha- 40 to condensation in the presence of an alkali to prepare a logenated C-C alkyl, amino, C-C alkylamino, compound of Formula I: C-Cohydrocarbonylacyloxy, C-Cohydrocarbonyla cylamino, Co-Co arylacyloxy, and Co-Co arylacy

lamino; or a tautomer, racemic or optical isomer, phar- I maceutically acceptable salt (which is water soluble), or 45 solvate thereof. 17. A method for preparing the compound of Formula I, its tautomer, its racemic or optical isomer, its pharmaceutically acceptable salt, or its Solvate according to claim 1, comprising the following steps: 50 a) converting an aromatic hydrocarbon compound of For mula VIII: R2 -N R1 VIII wherein: / \ 55 R' is selected from ethyl, propyl, butyl, and methoxyethyl: R4 x R’ is selected from 2-pyridinylmethyl, 3-pyridinylmethyl, 4-pyridinylmethyl, 2-morpholinylethyl, and 3-mor via Friedel–Crafts acetylation using Succinic anhydride to pholinylpropyl; form a ketonic acid compound of Formula VIII': R is 6-methyl or 7-methyl: 60 R is 1-3 substituents selected from H, halogen, alkyl, O VIII substituted hydrocarbonyl, alkenyl, substituted alkenyl, phenyl, substituted phenyl, heteroaryl, substituted het OH: eroaryl, C-C alkoxyl, Cs-Co aryloxy, Substituted ary RN N loxy, C-C alkylamino, Cs-Co arylamino, Substituted O 65 arylamino, di-(Cs-Co alkyl)amino, di-(Cs-Co aryl) 2 amino, di-(substituted aryl)amino, C-Co hydrocarbo nylacyloxy, Co-Co arylacyloxy, C-Cohydrocarbony US 8,980,887 B2 53 54 lacylamino, Co-Co arylacylamino, carboxyl, C-Co wherein: hydrocarbonyloxy formyl, C-C aryloxy formyl, ami R" is selected from ethyl, propyl, butyl, and methoxyethyl: noformyl, C-Cohydrocarbonylaminoformyl, or R’ is selected from, 2-pyridinylmethyl, 3-pyridinylmethyl, Co-Co arylaminoformyl; wherein the heteroaromatic 4-pyridinylmethyl, 2-morpholinylethyl, and 3-mor cycle is a monocyclic or fused aromatic hydrocarbonyl 5 pholinylpropyl; having 1-3 heteroatoms selected from N, O or S, each of R. Rare independently selected from H, halogen, alkyl, the Substituents of groups having Substituents is selected substituted hydrocarbonyl, alkenyl, substituted alkenyl, from halogen, hydroxyl, cyano, nitro, C-C alkyl, phenyl, substituted phenyl, heteroaryl, substituted het C-C alkoxyl, C-C alkylthio, mono- or di- or tri-ha logenated C-C alkyl, amino, C-C alkylamino, 10 eroaryl, C-C alkoxyl, Cs-Co aryloxy, Substituted ary C-Cohydrocarbonylacyloxy, C-Cohydrocarbonyla loxy, C-C alkylamino, Cs-Co arylamino, Substituted cylamino, Co-Co arylacyloxy, and Co-Co arylacy arylamino, di-(Cs-Co alkyl)amino, di-(Cs-Co aryl) lamino; or a tautomer, racemic or optical isomer, phar amino, di-(substituted aryl)amino, C-Co hydrocarbo maceutically acceptable salt (which is water soluble), or nylacyloxy, Co-Co arylacyloxy, C-Cohydrocarbony solvate thereof. 15 lacylamino, C-C arylacylamino, carboxyl, C-Co 18. A method of treating a translocator protein (TSPO)- hydrocarbonyloxyformyl, Co-Co aryloxy formyl, ami associated condition selected from the group consisting of noformyl, C-Co hydrocarbonylaminoformyl, or anxiety and depression comprising administering to a mam C-C arylaminoformyl; wherein the heteroaromatic mal in need thereof a therapeutically effective amount of a cycle is a monocyclic or fused aromatic hydrocarbonyl compound of Formula I: 2O having 1-3 heteroatoms selected from N, O or S, each of the Substituents of groups having Substituents is selected

from halogen, hydroxyl, cyano, nitro, C-C alkyl, C-C alkoxyl, C-C alkylthio, mono- or di- or tri-ha logenated C-C alkyl, amino, C-C alkylamino, 25 C-Cohydrocarbonylacyloxy, C-Cohydrocarbonyla cylamino, Co-Co arylacyloxy, and Co-Co arylacy lamino; or a tautomer, racemic or optical isomer, phar maceutically acceptable salt, or Solvate thereof. 19. The method according to claim 18 wherein the com N 30 pound is a TSPO ligand. k k k k k UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTION PATENT NO. : 8,980,887 B2 Page 1 of 1 APPLICATIONNO. : 13/805967 DATED : March 17, 2015 INVENTOR(S) : Rifang Yang et al. It is certified that error appears in the above-identified patent and that said Letters Patent is hereby corrected as shown below:

In the Claims

In column 49, claim 16, line 64, after “solvate according to replace “claims 1, with --claim 1,--.

Signed and Sealed this First Day of December, 2015 74-4-04- 2% 4 Michelle K. Lee Director of the United States Patent and Trademark Office