"...the step from the laboratory to the patient's bedside...is extraordinarily arduous and fraught with danger." Paul Ehrlich Baran Group Meeting Acridine Alkaloids Jonathan Lockner Dyes to Drugs: 1 9 8 acridine 2 7 dibenzo(b,e)pyridine Orange Dye 2,3,5,6-dibenzopyridine U.S. Patent 537723 A, April 16, 1895 (Swiss chemists) 3 N 6 2,3-benzoquinoline 4 10 5 10-azaanthracene Cancer Treatment Using Specific 3,6,9-Substituted Acridines WO2006095139, September 14, 2006 (Neidle et al) 3,6,9 are the important positions of acridine drugs flat (planar) aromatic, hydrophobic, pKa 5.6 colorless to light yellow crystals (mp 107-110 °C) chromatography on basic alumina MeO NHSO2Me irritating odor, lachrymator, carcinogenic, mutagenic H2N N NH2 → Bruce N. Ames (UC Berkeley) studied carcinogenesis/mutagenesis by NEt2 HN chemicals, including acridines (Science 1972, 176, 47) Cl- Me HN OMe 126.6 acriflavine N 9.09 8.19 135.8 129.5 Cl N 1H NMR: 13C NMR: 7.64 128.3 quinacrine/Mepacrine/Atebrin amsacrine/Amsidyl (antileukemia) H2N N NH2 (antimalarial) 125.5 N 7.89 N proflavine 130.3 8.22 "There is no exaggeration that [the 149.1 availabiilty of quinacrine] probably changed the course of history." L. J. Bruce-Chwatt 1870 → acridine isolated from coal tar (Carl Grabe & Heinrich Caro, BASF, Germany) Grabe introduced "ortho", "meta", "para" nomenclature 1895 → "Orange Dye" patent; acridines being used as fabric dyes & biological staining agents 1912 → Ehrlich & Benda proposed use of acridines as antimicrobials (acriflavine/Trypaflavin/Gonoflavin) Ehrlich (of Salvarsan "606" fame) first introduced idea of synthetic chemotherapy 1913 → Carl Browning identified proflavine, the neutral (non-methylated) version of acriflavine 1914-1918 → WWI; acridines as wound antiseptics in base hospitals on Western Front 1917-1946 → widespread clinical use of acridines as antibacterials during "antibacterial gap" 1939-1945 → WWII; quinacrine used in eastern theatres, in absence of quinine from Japanese-held Java 1946 → end of WWII, penicillins eclipse acridines 1970s → nitracrine/Ledarkin; amsacrine/Amsidyl for cancer treatment present → anticancer, anti-AChE, antiprion, antinociceptive 1 9 8 2 7 3 N 6 Baran Group Meeting 4 10 5 Acridine Alkaloids Jonathan Lockner Commercial Availability of Acridines: Acridine Isolation: O marine: plant: NH2 CO2H a) tunicates & ascidians a) bark of Australian scrub ash tree b) sponges c) sea anemones N H N N N 9(10H)-acridanone acridine 9-aminoacridine 9-acridinecarboxylic acid $18.84/g $3.23/g $1.19/g $21/g mp >300 °C mp 107-110 °C O O N H N O N O N N N N H2N N NH2 O acridine orange (AO) acridine yellow (AY) cystodytin A acronycine $2.56/g $2.19/g + H2N N NH2 Cl- Me H N N NH 2 2 H2N N NH2 Acriflavine (Trypaflavin) chrysaniline ("phospin") benzoflavin $0.87/g dyes silk & wool yellow $25.91/g staining with AO: Acridine Biosynthesis: HO OH OH CO2H + NH2 OH N OH anthranilic acid phloroglucinol 2,4-dihydroxyacridine (or equiv) (or equiv) Chem. Rev. 1993, 93, 1825 Adv. Het. Nat. Prod. Syn. 1992, 2, 377 Die Pharmazie 1970, 25, 777 Australian J. Sci. Research 1951, 423 1 9 8 2 7 3 N 6 Baran Group Meeting 4 10 5 Acridine Alkaloids Jonathan Lockner Using Acridine Dyes to Study Cellular Processes: absorption: 440-480 nm (blue) emission: 520-650 nm (green-red) N N N "metachromatic fluorochrome" NH2 acridine orange (AO) nucleic acid selective fluorescent dye N Br Useful for cell cycle determination: stain nucleic acids; flow cytometry N Hydrophobic → quickly diffuses into cell membrane, then complexes with DNA (green N O fluorescence) and RNA (red fluorescence) H AO/EDTA mixture used for 1) denaturing dsRNA, and 2) binding ssRNA 9-amino-6-bromo-DACA Darzynkiewicz, Z. Methods in Cell Biology 1990, 33, 285 Jaroszeski, M. J. Methods in Molecular Biology 1998, 91, 10 Cl J. Med. Chem. 1999, 42, 536 N acridinecarboxamide complexed with hexanucleotide d(CG(5-BrU)ACG)2 HN Cl (CG-preferential behavior associated with acridine chromophore) OMe Cl N quinacrine mustard MeO NHSO2Me fluorescence studies of plant, animal, human chromosomes Science 1970, 170, 762 O2N HN N HN N N Interaction of Acridines with DNA: nitracrine/Ledakrin amsacrine/Amsidyl (antitumor) (antileukemia) "Single action": 9-aminoacridine; quinacrine; acridine orange J. Med. Chem. 1992, 35, 4832 J. Med. Chem. 1974, 17, 922 1) intercalate DNA "Dual action": quinacrine mustard 1) intercalate DNA MeO NHSO2Me 2) form covalent bond with DNA NMe2 Intercalative activity (and thus mutagenicity) can be 'designed out' of the aminoacridine profile HN N N → Appropriately substituted acridines maintain anticancer potency by instead interfering with MeO topoisomerase II enzyme (e.g. amsacrine stabilizes DNA/topo II "cleavable complex") N N H Lerman, L. S. Proceedings of the National Academy of Sciences 1963, 49, 94 NO J. Antimicrobial Chemotherapy 2001, 47, 1 Me CONHMe 2 Current Med. Chem. 2002, 9, 1655 asulacrine/amsalog/CI-921 PZA/pyrazoloacridine (anticancer) (antitumor) J. Het. Chem. 1989, 26, 1469 J. Med. Chem. 1992, 35, 4770 Prager, R. H.; Williams, C. M. Science of Synthesis 2004, 15, 988 1 9 8 Demeunynck. M. Expert Opin. Ther. Patents 2004, 14, 55 2 7 Chiron, J.; Galy, J.-P. Synthesis 2004 313 Albert, A. The Acridines, 2nd ed.; Edward Arnold Ltd: London, 1966 3 N 6 Baran Group Meeting 4 10 5 Acridine Alkaloids Jonathan Lockner Usual Acridine Synthesis Methodology: From quinomethanes: CO2H Ph Ph Ph Ph Cu ZnCl2 H2N O OH NH2 X ! CO2H Cyclization 160 °C HO N HO NH2 4 h HO NH HO N Cu N N CO2H H H ! 2-carboxy-diphenylamine Acridone From nitroarenes (Tanasescu 1937): X H2N OH X = Halogen Ullmann-Jourdan Reduction R CHO 1 H2SO4 R1 O R2 OH O R1 NO 20 °C N+ R1 Cyclization: POCl ; H SO ; PPA, etc..., 2 3 2 4 Oxidation O- Reduction: Na, BuOH, !, etc..., + N R2 N R2 Oxidation: CrO3; NaOH aq.; FeCl3; HNO3, etc... N N H O- OH Acridine Acridane From diphenylamines and carboxylic acids (Bernthsen 1884): RCO2H R Pfitzinger 1886: improved by µW " ZnCl OH OH 2 (J. A. Seijas, M. P. Vazquez-Tato) O HO2C OH N 200-270 °C 120 °C N 4 h H O + N HO OH Via radical reactions of quinones (Chuang 1990): H N OH O O CO2Et Friedländer: Mn(OAc)3 Cl Cl O MeCN 120 °C + NC CO2Et 58% N 80 °C, 36 h N + H 43% O O NH3Cl O N Via aza-Diels"Alder (del Mar Blanco 2000): Ullman 1906: NMe2 N O NaOAc Ph N O MeCN, 70 C O O N 150 °C O N ° 2 Ph 88% 2 + then NaOH + H N N Cl 2 N NH O 43% O O CF3 K CO alumina OMe 2 3 OMe From acylated diphenylamines: + Cu, CuI 20% Br N OMe H2N OMe Ph Goldberg: I , HI, h# Cl 2 N CO2H 63 % CO H POCl3 H N 2 K2CO3, Cu + O Ph reflux, 1 h N Cl H2N CyOH, reflux N H 1 9 8 2 7 3 N 6 Baran Group Meeting 4 10 5 Acridine Alkaloids Jonathan Lockner Reductive Alkylation: nBu Electrocyclizations: Ring Expansion: h N Cl h" " AcO OAc OH OH N N nBuCO H ! N2 N N 2 N ! CO O Tetrahedron 1969, 25, 1125 H2SO4 ! HCl O 64% Photoalkylation: CH2OH ! CO2 N O O h" H Ring Contraction: NH OH N OH P H OH H N+ CH3OH N X- Via arylation of phenylacetonitriles (Makosza 1973): I2, AcOH Me Me Cl N Chem. Ber. 1964, 97, 2418 CN peracids H H2O N Et CN Et Et dibenzazepine 92% O N 90% aq H2SO4 Et 2 NH2 + CN 50 °C, 2 h + BF3•OEt2 PTC O2N N N Dehydrogenation: O- Pd/C PhH PCl N3 N 95% 3 5% 65 °C, 80 h N 270-300 °C N 69% Photolysis or pyrolysis of aryl azides: 6 h ARKIVOC 2006, (xii), 111 700 °C 350 °C Substitution at 9-position: 95% 90% N N N iPrCO H 3 H 2 AgNO3 From diarylamines (this example also shows that carbonyl can be generated after N-arylation): N H2SO4 N (NH ) S O NH 4 2 2 8 2 CHO I2 PbO2 + O N 240 °C N N MeO OMe NH2 N N Li H H MeO OMe N Via the McFadyen!Stevens Reaction: THF, !70 °C TMS 88% N O CO Me H 2 N CHO SOCl2 TsN O NaOH H2NNH2 Acridine 10-oxides: then O N 100 C, 2 h TsNNH N ° KO2, DMSO H 2 H 73% Cl N Cl rt, 18 h H Cl mCPBA 61% 59% N N N OH + AcOH, HCl N N+ CN - NH HN O 120 °C, 1 h N KCN 100% K [Fe(CN) ] Cl NiCl2•2H2O, Li, biphenyl 3 6 N+ Cl Cl 70 C, 3 h 64% ° - 35% O 1 9 8 2 7 3 N 6 Baran Group Meeting 4 10 5 Acridine Alkaloids Jonathan Lockner Drug Synthesis: OH Cl CO2H 1. KCN NaBH4 OMe 2. NaOH O N Cl N Cl CO H CO2H N Cl 2 H2N OMe POCl3 H OMe Ac Ac Cl Cl Cl N PPA H Cl N Zirkle et al J. Org. Chem. 1961, 26, 135 H P2O5 Mietzsch et al U.S. Patent 1938, 2113357 OPOx 1. H2 N N NEt2 Cl 2. Me2N(CH2)3Cl HN Cl H NMe NaH Cl N Cl Bayer 1932 OMe NEt OMe 2 H H N 2 important WWII drug; 2 chlorimipramine cf. quinine (antidepressant) Cl N Cl N quinacrine/Mepacrine/Atebrin (antimalarial) H NOC O CONH 2 2 O O O NMe2 NMe2 O N O ClMg NMe H2 NaNH NH N 2 Cl Cl H 2 2 H Cl ! N N Bielavsky Collect.