Short Stories in Pharmaceutical Discovery, Process and Isotopic

Short Stories in Pharmaceutical Discovery, Q. Michaudel Process and Isotopic Labeling Baran Lab GM 2011-11-19

Some data about some common radiolabels: There are three different but complementary ways to explore medicinal chemistry, every having its own constraints:

Isotope Type Decay Half-life Medical use Discovery, hit-to-lead, and lead optimization: * rapidity * development of a chemical library 3 natural 3He, – 12.32 years analytical Process chemistry and development: * scalable synthesis (yield optimization, ease of T (trace) β puriﬁcation, cost, safety) for bulk industrial production 11C artiﬁcial 11B, β+ 20.38 min PET imaging Isotopic labeling: * availability and price of labeled reagents * reaction times for radiochemistry (tomography...) natural 14 14N, β– 5,730 ± 40 analytical C (trace) years

Route Discovery Process Labeling 13N artiﬁcial 13C, β+ <10 min PET imaging

15 15 + Typical O artificial N, β 122 s PET imaging scale 1 mg < x < 1 kg > 100 kg ~100 mg synthesis 18F artificial 18O, β+ 109.77 min PET imaging Isotopic labeling synthesis, a few definitions: 99mTc artificial 99Tc, γ 6.01 h imaging This technique is used for metabolic and pharmacological studies. Radiolabeled compounds allow for measuring absorption, distribution, metabolism, and elimination of SPECT 123 123Te, EC compounds from the human body. Stable-labeled molecules often serve as internal I artificial 13.3 h imaging standards in mass spectrometry and NMR studies. Radioactive molecules are also used in imaging and radiation therapy. 131 – radiation 131I artificial Xe, β 8.02 h therapy Radioactive isotopes: 3T, 11C, 14C, 13N, 15O, 18F, 35S, 124I, 131I... Diagnostic medical imaging: 3 main techniques, all using gamma cameras Stable isotopes: 2D, 13C, 15N, 17O, 18O... * Scintigraphy: 2D imaging Isotopomers or isotopic isomers: two molecules with the same number of each isotopic * SPECT (Single-photon emission computed tomography): 3D imaging by reconstitution, directly detects gamma rays atom but differing in their positions, e.g.: * PET (Positron emission tomography): 3D imaging by reconstitution, detects gamma rays produced by annihilation of a positron and an electron 2D 2D 2D Note: Radiography uses electromagnetic radiation (X-rays) and does not require any 2 Me Me Me CH2 D Me OH Me OH radioactive molecules!

H O, H 18O, Isotopologues: molecules only differing in their isotopic constitution, e.g.: 2 2 2 D2O... 1 Short Stories in Pharmaceutical Discovery, Q. Michaudel Process and Isotopic Labeling Baran Lab GM 2011-11-19

Production of small radioactive building blocks:

Small radioactive molecules (e.g. CO2) are produced in a cyclotron and chemically transformed. Enzymatic transformations have also been developed. For example for 11C labeling: 11 CH3SH CuSO4 Na2S2O5 R3P 11 CH3IH H Pt, NH3 I2 n–BuLi N 11 H11CN 11CH 11CH I 11CH Li Cu CN Br3 4 3 3 11 AgNO2 CNBr 11 11 Cl2 CH3NO2 Fe/O2 CCl4 Ni, H HI 2 Fe–Mo LiAlH PtCl4 Zn 4 cat 11 11 11 11 11 SPECT scanner COCl2 CO CO2 CH3OH H CHO

source: UCAIR website MeLi K, http://www.ucair.med.utah.edu/ NH3 NH What_is_SPECT.html 3 11 11 11 Me2 CO R CH2OH R CHO 11 11 CO(NH2)2 K CN Common radiopharmaceuticals 11 for 18F PET: R CH2NO2

HO Handbook of radiopharmaceuticals : radiochemistry and R11CH I R11CH Li applications / editors, Michael J. Welch, Carol S. Redvanly 3 2 Published !Chichester, England ; Hoboken, NJ : Wiley, HO 18F c2003 11 R CH3SH CO H 2 Stable isotope natural abundance: 2D : 0.0156% 13 NH 2 CH3OH (99%): $167.00/1g 2 13 13 2 2 C: 1.1% C D3O D (99%, 99.5%): $277.50/1g 15N: 0.00364% 13 18F-Fluoro-Dopa CH2O (99%): $368.50/1g 18 13 O: 0.00205% H CO2H (99%): $363.50/1g 17 13 O: 0.00038% COCl2 (99%, 1M in benzene): $396.50/5mL Price examples of stable-labeled OMe N building blocks (Sigma-Aldrich): 15 N NH3 (98%): $432.00/1L 2D O (99.994%): $12.40/1g N N O 2 2 18 C D3OH (99.8%): $39.90/1g H2 O (99%): $992.00/1g 18F PET principle 2 2 2 18 C D3O D (99.96%): $48.30/1g D2 O (95%): $839.00/1g 2 2 18 C D O in D O (98%): $19.83/1g CH3 OH (95%): $993.00/1g source Dr. Bernard Langlois Fluorine Chemistry 2 2 MPPF 2DCO 2D in 2D O (99%): $42.00/1g class 2 2 18F 2 17 C6 D6 (99.96%): $18.58/1g CH3 OH (20%): $1,290.00/1g!!! 2 Short Stories in Pharmaceutical Discovery, Q. Michaudel Process and Isotopic Labeling Baran Lab GM 2011-11-19 OH Me Synthesis of small labeled molecules: O 17 17 2 H2 O H2 O Activity (A) = # decays per seconde N A(final product) Radiochemical yield (RY): RY = x100 OH Me 17O A(starting material) 17 O2 Specific activity (SA): activity for one mole. Unit = Ci/mol with Ci = 3.7x1010 Bq = 37 GBq O Me O 13 BH3 NH3 + H 17O B 2 H2 2 2 13 NH2 3 8 THF 8 3 NaOCl 8 N Appl. Radiat. Isot. 43, 389 O Me J. Label. Compd. Radiopharm. 2010, 53, 78 13 NH3 AgNO3 NaCl 13 13 2+ 13 K2PtI4 ( NH3)2PtI2 ( NH3)2Pt(H2O)2 ( NH3)2PtCl2 HCl gas 18 18O Cisplatin, RY: 27% H2 O O O J. Label. Compd. J. Nucl. Med. 27, 399 Me Me Radiopharm. 1995 26, 1077 80°C, 87% Me H Me NH2 R1 11C 1. Me2NH2ClO4 Br OH 3T OH J. Label. Compd. Radiopharm. N O H H 11 1999, 36, 33 HO N Me HO N Me 2. CH3NO2, 3 R1 1. T2, Pd/C tBuOK R2 EtOH R2 3. Na2S Br Br 3T 3T Zincke aldehyde 2. HCl OH OH 18 OMe OMe K F, [3T](R,R)–4–methoxyfenoterol OAc Kryptofix OAc OH J. Label. Compd. Radiopharm. 2010, 53, 68 OTf 2.2.2, HCl O O O Cl Cl OAc OAc AcO AcO HO 125 MeCN, 80°C, 55% H2N OH chloramine-T I H2N OH AcO AcO 18 (2 steps) HO 18 OH 125 5 min F F Na I N O N O J. Nucl. Med. 27, 235 2–deoxy–2–[18F]Fluoro–D–glucose prepared in ca. 50min EtOH, pH = 7 18FDP is commonly used for PET [125I]Melphalan J. Label. Compd. Radiopharm. 2010, 53, 68 N O O Cl Cl OH 3T , Pd/C 3T 3T O 2 6N HCl OH NH CO2H 14 N N ClH3N BrCH2CO2Me, CH3I EtOH 3T 3T NNa O CH3ONa NH 2–aminopyridine O O S S N Named reaction? 14 J. Label. Compd. Radiopharm. O O S CH3 O O 14 2008, 51, 113 J. Med. Chem. 1999, 42, 5235 [ C]Piroxicam O O 3 Short Stories in Pharmaceutical Discovery, Q. Michaudel Process and Isotopic Labeling Baran Lab GM 2011-11-19

Temozolomide (Temodar, Merck): O O O 3. 2-mercaptopyridine- N-oxide, * anticancer drug (astrocytoma (brain tumor) and melanoma) Et3N, –15°C O O N N Temozolomide * prodrug, DNA methylating agent N N 4. Bu3SnH, AIBN N (cat), DMF, hν, rt O 21% (4 steps) Discovery route: J. Med. Chem. 1984, 27, 196 NH2 Me O N N N Process route: JCS Chem. Commun. 1994,1687 N Isotopic labeling route (2002): 11C N Isotopic labeling route: J. Med. Chem. 2002, 45, 5448 NH2 O O O all three papers are from Malcolm F. G. Stevens O Cl Me H 11C N N 3 1. Cl O N N N N Discovery route (1984): N N N 11 N 2. CH3I NH 1. dry HCl 2 NH2 O O EtOH:Et2O CO2Et > 0°C, 24h H2N CONH2 PhN2Cl H2N CONH2 O NC H2N 2. sat. NH3 H O, pH = 4 2 H2NOC N2 H2NOC HN N 11 N EtOH, rt, 5d HN HCl rt, 90% HN N N MeNH2 COCl2 HCl N 60% (2 steps) Ph N N 55% N N N NH N NH 11 JACS, 1945 67, 1017 HCOOH, C Me Pd/C 30%, H2, J. Biol. Chem. 1949, 181, 89 O H2O:2-Methoxyethanol JOC 1959, 24, 256 11 11 rt, P > 1 atm, 3-4h COCl2 + MeN(SiMe3)2 –> MeN CO + 2 MeSiCl or 11 11 TL, 1979, 4253 then HCl reﬂux 15min, 71% COCl2 + MeNSO –> MeN CO + SOCl2 O and 1. aq NaNO 11 11 2 CH3I + AgOCN –> CH3NCO + AgI Me 1N HCl, H2N CONH2 O radiosynthesis N N 0°C, 70% 11 time: ~47 min N H3 C N N N -1 Temozolomide 2. Methyl HN NHCl SA = 64 GBq.µmol N isocyanate N DCM, dark, rt, NCO N NH2 11 CH3 N O 98% Mechanism? NH2 H2NOC N2 O Process route (1984): avoiding the use of Methyl isocyanate (Bhopal disaster, 1984) O O N NH H2N

H2N CONH2 1. EtO CCH NCO N 2 2 EtO2C N N MeN DMSO, pyr, 20°C 1. 5N HCl, 45°C 11 N N CO N radiosynthesis N N N time: ~50 min HN NHCl N 11 2. aq NaNO2 2. Me CHCH OCOCl, C Me 2N HCl, 0°C 2 2 SA = 52 NH2 NMO, DMF, –15°C O -1 72% (2 steps) O GBq.µmol 4 Short Stories in Pharmaceutical Discovery, Q. Michaudel Process and Isotopic Labeling Baran Lab GM 2011-11-19

Brivanid (under evaluation, BMS): 13 13 13 O EtO2 C CH3 H3 C 13 1. NaH, NH2Cl, * anticancer C13C 13 * VEGFR-2 kinase inhibitor (tyrosine kinase vascular endothelial growth factor DMF, 0°C, 55% C 15NH 13 13 receptor-2): slow down angiogenesis and tumor progression CO15NH EtO2 C C 30% 15N 2 2. HC(OEt)3, 15N H p–TSA (cat), N H Me2NC(O)Me, N Discovery route: J. Med. Chem. 2006, 73°C 49, 2143 Me The same synthesis has been used to do a 14C-labeling of the core: Process route and isotopic labeling Me Me O (R) route: J. Label. Compd. Radiopharm. F 2011, 54, 324 EtO2C Me EtO2C Me N 1. NaH, NH2Cl, HO O DMF, 0°C, 55% N O N CONH 14 N 2 2. H C(OEt)3, p–TSA N H (cat), Me NC(O)Me,73°C 2 N NH 14 Synthesis of the pyrrolotriazine core in the discovery route: C H Bioorg. Med. Chem. Lett. 2005, 15, 1429 Completion of 13C, 15N-labeled Brivatid synthesis with the discovery route: H MeO2C Me N MeO C Me 1. TosMIC, NaH, 2 1. Ph P(O)ONH Me Me 2 2, 13 O 1. POCl DIEA, DMSO:THF NaH, DMF H3 C 3, O toluene, 110°C, O 13 H 13C N C 15NH 98% 3 2. AlCl3, CO2Me CO2Me N 2. HCONH Δ 13 13 13 F CCl COCl, 2, EtO2 C C C 3 H N NH 15N 2. 4-Fluoro-2-methyl- 15N then NaOMe, 13 13 N EtO2 C C MeOH 1H-indol-5-ol, DMF, 15N Named reaction for 1.? K2CO3, rt, 66% N

1. LiCl, CH3MgBr, H Synthesis of the pyrrolotriazine core in the isotopic labeling route: 13C, 15N THF/Toluene (1:1), 56% N Me 2. 50% H2O2, BF3OEt2, J. Label. Compd. Radiopharm. 2006, 49, 139 CH2Cl2, 68% 13 O H3 C Me 13 F 15NH OH, 45°C, 3. Et N, LiCl, Me C 15 O O 4 O O 3 N overall yield for pressure tube O O EtOH, 58% O 13C the 5 steps: 14% O 15N 13 13 HO 99% 15 15 C C N MeO OMe H2 N NH2 13 13 H3 C C OEt 15 AcOH Cl NH2 What about the process route? NMe2 HCl 13 15 O O 15 C, N-labeled Brivatid has also been synthesized from the same core intermediate O O rt 18h NH HCl MeO OMe with the process route. This route is somehow similar to its precedent, with some 13C 13C 13C 13C then 15 15 13 13 13 13 100°C H2 N NH2 H3 C C OEt H3 C C OEt optimized conditions, one supplementary protection/deprotection sequence and the H2 p–TSA (cat), 6h oxidative decarbonylation of the pyrrole moiety being done prior to the indole arylation. 80°C O O Me2N Overall yield for the 7 steps: 24%! 5 Short Stories in Pharmaceutical Discovery, Q. Michaudel Process and Isotopic Labeling Baran Lab GM 2011-11-19

Tipranavir (Aptivus, Boehringer-Ingelheim (Pharmacia & Upjohnʼs)) 1. Ti(OnBu)Cl O Et 3, * combination therapy to treat HIV infection 1. TiCl4, DCM, –78°C DCM, –78°C 2.DIEA N(Bn)2 2.DIEA * inhibits the replication of viruses Me O Discovery route: J. Med. Chem. 1998, 3. O OMe 3. 41, 3467 O XA Ph Me CF3 O Me OH N Process route: JOC 1998, 63, 7348 4. aq. HClO4 Me H 65%, 25:1 dr 3α N 95% (4 steps) Isotopic labeling route: J. Label. Me (R) S 1. KOtBu, THF, 0°C (R) Compd. Radiopharm. 2008, 51, 314 O O 2.H Pd/C, Me OH O Et 2, 6 O O N(Bn) MeOH:EtOAc Ph 2 Tipranavir Ph 3. A, pyr, DCM 54% (3 steps) The discovery route: O XA O O This synthesis actually allowed for the elucidation of the absolute streochemistry of Tipranavir OH Me OMe The process route: OH OH 1. AlCl3, OLi 1. NaH (2 eq), m–nitrobenzaldehyde cocrystallization Ph nPr THF Me THF 1. Me O with norephedrine O n 2. NaOH then 2. AlEt CuBr Me S Ph Pr THF 27% O 3, 2 n n O H O+ O Pr Pr 3 Ph THF, 80% (2 steps) 2. NaOH, MeOH, 95% OH OH 72% (2 steps) O (2 steps) O O Me Ph Ph OH 1. H Pd/C, CF3 2, N MeOH, 92% H OPOM POMCl, DIEA, NO2 1. DIBAL–H 76% Tipranavir Cl Me n n 2. HPLC chiral S Pr OPOM 2. TEMPO, NaOCl, Pr OPOM resolution of Cbz O A O O O 78% Ph derivative 3. A, pyr, DCM Ph Ph This route allows for diversity at C3α, C6 and sulfonamide Et Et Et The ﬁrst asymmetric synthesis: isopropenyl acetate Amano P30 lipase NO2 NO2 NO2 HO AcO HO O O O O Et + 1. CuBr Me2S, B ~50% conversion THF, 0°C N(Bn)2 O N Et O N 2. Na2CO3, BnBr, Et 1. MsCl H2O:DCM 2. NaC H O 78% (2 steps) Ph Cl NO 7 11 4 Ph BrMg 2 O 3. 6N HCl POMCl MeO C 4. HCl, MeOH JACS 1997, 119, 3627 B 2 N(TMS)2 6 Short Stories in Pharmaceutical Discovery, Q. Michaudel Process and Isotopic Labeling Baran Lab GM 2011-11-19

Et OH Et NaHMDS, 90% O CO NO2 ACIEE 2002, 41, 1929 NO2 nPr H N N Mo MeO C Ph O CO2Me 2 nPr OC POMO Nu H N O H Ar Ph OH Et R 1. PCC 1. H2, Pd/C, 2. H2SO4 NO2 MeOH Tipranavir Me Me O 3. NaOH, MeOH, nPr 2. A, pyr, DCM, CHO 75% (3 steps) 78% (2 steps) Me 1. NaHMDS, Me O O 17 steps, 2 THF, -78°C Ph resolutions + OPMB MeO2C 2. DMP, DCM, rt, CO2Me A more academic route? The use of DYKAT (Dynamic kinetic asymmetric transformation) (89% two steps) OPMB Ph Ph Trost, JACS 2002, 124, 14320 NO2 NO2

O PMBOH, Et3B, 1 mol %

1.CH2CHMgBr, Pd2(dba)3 CHCl3, 3 mol OH Me Me 1. CAN, MeCN/H2O, 88%. THF, 0 °C O % (S,S)–L1 1 mol % 2. NaOH, MeOH, 4°C, 77% (97% brsm). 2. 1N NaOH, 69%, 98% ee. OPMB 3. 5 mol % Pd/C, H Et O, 25°C, 86% 2, Me Cl 2 MeOH, rt (two steps) L1 Tipranavir 18 steps, overall yield: 25%! O O Et Et 4. 5-(Trifluoromethyl)-2- NH HN pyridinesulfonyl chloride, (S,S) B DCM, pyr, DMSO, -25 °C, OH PMBO O 1. PhI, 10 mol % 92%. PPh2 Ph2P Pd(OAc)2, 40 mol % P(o-Tol) toluene, 1. Catechol 3, borane, 1 mol % The isotopic labeling route: 14C and 13C nPr Et3N, reflux Pd O (Ph3P)3RhCl, THF CHO 1. O O 2. 5 mol % Pd/C, H2 Me Me L L , then 3 N NaOH, O 1. SOCl2 14C Ph MeOH, Pyr, rt 2. Cd(Et)2 30% H2O2, rt. Et OPMB OPMB 14C 3. DMP, DCM, rt Ph OH 3. 90% HNO TiCl pyr, THF 2. DMP, DCM, rt, 3 4, 4. Ph P=CH THF, 72% (3 steps) 2. [((R,R)–MeDuPHOS)Rh(cod)]BF 3 2, Ph 88% (two steps). Ph 4, reflux, H2, (80 PSI), 57°C 86% (4 steps) JACS 1998, 120, 12702 NO2 63% (2 steps) OH Et 1. Boc O, DCM, Et N, 2 3 1. H2, Pd/C, DMAP, rt, 98% NO2 MeOH Me 14 2. 10 mol % L2 [ C]Tipranavir Mo(CO)3(C7H8), 15 mol n 2. A, PhNMe BHT, O O Pr 2, 7 steps (25%), SA = 54 % (R,R)–L2, dimethyl NH HN O O DCM, 58% (2 HO Ph mCi/mmol steps) 13 sodiomalonate, THF, (R,R) C CO2H MeO C 13 13 reflux, 94%, 96% ee. 2 N N C C 3. NaCl, 150 °C, 13 13 13 Synthesis of [ C6]Tipranavir with the same route starting with: C C NO2 20:1 DMSO/H2O,100%. NO2 13C 7 Short Stories in Pharmaceutical Discovery, Q. Michaudel Process and Isotopic Labeling Baran Lab GM 2011-11-19

BMS-644950 (in clinical development) The process route goals: more convergence, no chromatographies, avoiding production of MeSH (in synthesis of * anticholesterol, statin type triazole D), highly ﬂammable and toxic gas, avoiding epimerization at C5. * Inhibits cholesterol synthesis HO 1. CuCl (0.01 eq.), F F MeO O 5 CO2H H2SO4 (0.1 eq.), MeOH, CO2MeMe Me reﬂux F OH Me CHO Me + Me 2. Cool to 20°, Discovery route: J. Med. Chem. 2008, 51, 2722 crystallization, 85% HN NH Me O H2N NH2 Named reaction? N N Process route: OPRD, 2010, 14, 441 O

Isotopic labeling route: J. Label. Compd. O N N Radiopharm. 2011, 54, 72 Me First oxidation conditions were 65% HNO3, but... "If this reaction were to reach >40°C, then it would become unstoppable until all the reagents are consumed". N N Me 1. CuCl2 (0.01 eq.), 1. KOtBu, D, K2CO3 (0.1 eq.), H2N SMe F THF:DMF, rt F HO The discovery route: tBuOOH (2.2 eq), CO MeMe Me 2 2. (MeO)2CO, 1. H2SO4 DCM, 40°C NH F DABCO F 2 CO2Et Me CO Et Me Me Me HMPA 2 then work-up and 3. DIBAL–H, crystallisation, N N toluene N N Me Me 80% (3 steps) 2. DDQ/, DCM 88% O 3. m–CPBA, N N Cl N NMe 1 step from 48% (3 steps) 2. POCl3, 95% commercially available compounds NMe SO2Me N Me Me Bioorg. Med. Chem. 1997, 5, 437 BMS-644950 35% overall yield!!! O ammonium salt CO tBu 1. DIBAL–H, DCM 2 similar steps to the 2. TEMPO, NaOCl, F O 1. LiHMDS, D (2.5 eq), discovery route, but EtOAc improved Me –60°C BMS-644950 sodium salt 3. LiHMDS, C, THF, 2. LiHMDS, MeI New synthesis of aminotriazole D: –78°C, Me 3. aq. HCl, THF 60% (3 steps) 4. NaOH, THF MeO N C NH N C N N NH2 N N 7 steps from 2 MeNHNH2 70% (4 steps) + Me NH Named reaction for 3.? known pyrimidine, NMe2 2 MeOH, 30–40°C N N SO Me 42% overall yield MeO Me2N D Me 2 0°C–10°C Me Me (20% real overall C yield) O The isotopic labeling route, an adaptation of the process route: 14C Ar N N O N N H2N SMe N NH2 MeNHNH2 H2N NH2 14 N S + MeSH 14C is used in the ﬁrst step, ultimately leading to MeN C R t D O O O Bu NH N Het N Ph O then HCO2H N O Me i H2SO4 SA = 21.8 mCi/mmol Pr 8 Short Stories in Pharmaceutical Discovery, Q. Michaudel Process and Isotopic Labeling Baran Lab GM 2011-11-19

HN HN Dasatanib (Sprycel, BMS) 14 C S O Me 14C S O Me * antileukemia H2N HN * Src tyrosine kinase inhibitor O NH O NH Me OH N OH Cl Cl N N N Cl N Me N Cl Me NH Discovery route: J. Med. Chem. 2004, H 47, 6658 N N N S (see also, J. Med. Chem. 2006, 49, H2N S O Me 6819) 14 HN O C Cl N Me S O Me 14C Cl NaOtBu Isotopic labeling route: J. Label. N NH Compd. Radiopharm. 2008, 51, 41 N THF, 82% NH Cl The discovery route: Cl OMe 1–(2–hydroxyethyl)piperazine, 1. NaH, 4–amino–6– DIEA, nBuOH 1. n–BuLi, 2–chloro–6– chloro–2– [14C]Dasatanib SA = 18.3 mCi methylphenyl isocyanate, methylpyrimidine, 66% N THF, –78 °C, 86% THF, reflux, 83% Me Cl N 2. TfOH, TFA:DCM S 2. NaH, 4–methoxybenzyl Me chloride, THF, 95% N (1:1), 99% N 18 Cl F S N N N Br NaI, Cs CO Cl O 2 3 N DMF:MeCN 1:1, Me NH 140 °C, 40 min [18F]Dasatanib Me H 1. 1–(2– analog Me hydroxyethyl)piperazine, N S 18F H N N N 1,4–dioxane, reflux or TsO N Dasatanib O chloride salt DMSO, 160 °C, N 2. HCl, Et2O, Cl 30 min. RA = 25.1 5.8% S H Cl MeOH, ± Cl O 91% (two steps) 6 steps, 61% average SA = 2560 mCi/µmol overall yield! K18F, Kryptofix 2.2.2,

K2CO3, o–dichlorobenzene, 105°C, 10 min The isotopic labeling route: 14C, 18F S OTf 18F Br Br 14 O Me C Br O Me H2N NH2 NBS K18F, Kryptoﬁx 2.2.2, O NH O NH THF:H O K2CO3, MeCN, 110°C, 10 min 2 OH OTs 18F 98% TsO TsO Cl Mechanism? Cl

9 Short Stories in Pharmaceutical Discovery, Q. Michaudel Process and Isotopic Labeling Baran Lab GM 2011-11-19 Me O LY2784544 (human clinical trials phase, Lilly) N N NH * anti myeloproliferative diseases N 2 Me * JAK2 protein tyrosine kinase inhibitor PMB N Pd2(dba)3, Xantphos N Me TFA, NaOH, PhMe:H2O N anisole O N N N LY2784544 H N 79% PMB 79% Me Discovery route: U.S. Pat. Appl. Publ. US 14 steps, 4.3% yield N 20100152181 A1 20100617 F over the longest linear HN Me sequence N Process route: OPRD, ASAP, Cl N N N doi:10.1021/op200229j H Pyrazole synthesis: O Isotopic labeling route: coming soon??? Me 1. p-anisaldehyde PMB CN EtOH, reflux BocHN NH H N NH F 2 2 N 2. H (15 psi), Pd/C NH 2 2 HCl HCl, dioxane N 2 Cl EtOH, 10–20°C reflux, 68% 3. AcCl, MeOH, 40– PMB The discovery route: 50°C, 68% (3 steps) Me O OMe The process route: N OMe NH2 Me2N N NMe 2 N N Cl Cl N cyclopentyl N N N NMO (10 eq) N Et3SiH (6 eq) Cl Cl Me N Me N Me N methyl ether, N Cl VO(acac)2 (20 mol%) TFA (11 eq) N 90°C, 77% N Me DMF EtOH, 40°C, 80% 85°C, 94% O O O O 120°C O 68% Cl Cl F O Cl F SOCl2, hex:MeOH N Cl F Me NaOH workup obtained with Cl F Cl F 70% a similar N O synthesis to 1. N the discovery Cl NH NPhth N N N N 2 1. AcOH, HCl, 100°C route, with Me tBu optimizations LY2784544 2. NaBH4, MeOH, 5°C PhthN CO H Pd2(dba)3, Xantphos 2 N O N AgNO TFA, 3. Cl Cl NaOH, xylenes:H2O, reflux 3, Cl Cl 2. TFA:H O (1:5), reflux, (NH ) S O N K2CO3 N 2 4 2 2 8, N Me N Me 66% (2 steps) NH Cl F 4. TFA, PMHS, PhMe, 80°C 2 Me MeCN:H2O, 70°C, 57% 5. 6N HCl, PhMe CN 8 steps, 35% yield over O 45% (5 steps) NaOH 2N HCl + N the longest linear Phth = Phthalimide NH2 t 90°C, 86% N sequence!!! Cl F PHMS = Polymethylhydrosiloxane Cl F BuHN NH2 tBu 10 Short Stories in Pharmaceutical Discovery, Q. Michaudel Process and Isotopic Labeling Baran Lab GM 2011-11-19

CO2H Other examples: Cl O BMS-587101 N S Discovery route: J. Med. Chem. 2006, 49, 6946 N N Cl N Process route: OPRD 2010, 14, 553 Me O Me Me Me Isotopic labeling route: J. Label. Compd. O OH O Radiopharm. 2009, 52, 236 H H N N N OMe 14CN 2 OC D3 N N H H O O Ph Me Me Me

Atazanavir (Reyataz, BMS) Discovery route: J. Med. Chem. 1998, 41, 3387

Process route: OPRD 2002, 6, 323

Isotopic labeling route: J. Label. Compd. Radiopharm. 2005, 48, 1041

14C N 14 H2N C O N Saxagliptin (Onglyza, BMS and AstraZeneca)

Discovery route: J. Med. Chem. 2005, 48, 5025

Process route: OPRD 2009, 13, 1169

Isotopic labeling route: J. Label. Compd. Radiopharm. 2007, 50, 1224 Automated system for the radiosynthesis of [3–N–11C-methyl]temozolomide from [11C]iodomethane via [11C]methyl] methyl isocyanate J. Med. Chem. 2002, 45, 5448 11