Synthesis of HCV Replicase Inhibitors: Base-Catalyzed Synthesis of Protected α-Hydrazino Esters and Selective Aerobic Oxidation with Catalytic Pt/Bi/C for Synthesis of Imidazole-4,5-dicarbaldehyde
摘要:
A robust convergent synthesis of the prodrugs of HCV replicase inhibitors 1-5 is described. The central 5H-imidazo[4,S-d]pyridazine core was formed from acid-catalyzed cyclocondensation of an imidazole-4,5-dicarbaldehyde (20) and a alpha-hydrazino ester, generated in situ from the bis-BOC-protected precursors 25 and 33. The acidic conditions not only released the otherwise unstable alpha-hydrazino esters but also were the key to avoid facile decarboxylation to the parent drugs from the carboxylic ester prodrugs 1-5. The bis-BOC alpha-hydrazino esters 25 and 33 were prepared by addition of ester enolates (from 23 and 32) to di-tert-butyl azodicarboxylate via catalysis with mild inorganic bases, such as Li2CO3. A selective aerobic oxidation with catalytic 5% Pt-Bi/C in aqueous KOH was developed to provide the dicarbaldehyde 20 from the diol 27.
Synthesis of HCV Replicase Inhibitors: Base-Catalyzed Synthesis of Protected α-Hydrazino Esters and Selective Aerobic Oxidation with Catalytic Pt/Bi/C for Synthesis of Imidazole-4,5-dicarbaldehyde
摘要:
A robust convergent synthesis of the prodrugs of HCV replicase inhibitors 1-5 is described. The central 5H-imidazo[4,S-d]pyridazine core was formed from acid-catalyzed cyclocondensation of an imidazole-4,5-dicarbaldehyde (20) and a alpha-hydrazino ester, generated in situ from the bis-BOC-protected precursors 25 and 33. The acidic conditions not only released the otherwise unstable alpha-hydrazino esters but also were the key to avoid facile decarboxylation to the parent drugs from the carboxylic ester prodrugs 1-5. The bis-BOC alpha-hydrazino esters 25 and 33 were prepared by addition of ester enolates (from 23 and 32) to di-tert-butyl azodicarboxylate via catalysis with mild inorganic bases, such as Li2CO3. A selective aerobic oxidation with catalytic 5% Pt-Bi/C in aqueous KOH was developed to provide the dicarbaldehyde 20 from the diol 27.
Imidazopyridazine Compounds for Treating Viral Infections
申请人:Leivers Martin
公开号:US20110052534A1
公开(公告)日:2011-03-03
Disclosed are compounds and compositions of Formula (I), pharmaceutically acceptable salts and solvates thereof, and their preparation and uses for treating viral infections mediated at least in part by a virus in the Flaviviridae family of viruses:
Imidazo[4,5-d]Pyridazine Compounds For Treating Viral Infections
申请人:Leivers Martin
公开号:US20110053892A1
公开(公告)日:2011-03-03
Disclosed are compounds and compositions of Formula (I), pharmaceutically acceptable salts and solvates thereof, and their preparation and uses for treating viral infections mediated at least in part by a virus in the Flaviviridae family of viruses:
ANTI-VIRAL COMPOUNDS, COMPOSITIONS, AND METHODS OF USE
申请人:Leivers Martin Robert
公开号:US20090197880A1
公开(公告)日:2009-08-06
Disclosed are compounds of Formula (I), pharmaceutically acceptable salts and solvates thereof, compositions thereof, and methods for their preparation and uses for treating viral infections mediated at least in part by a virus in the Flaviviridae family of viruses.
Synthesis of HCV Replicase Inhibitors: Base-Catalyzed Synthesis of Protected α-Hydrazino Esters and Selective Aerobic Oxidation with Catalytic Pt/Bi/C for Synthesis of Imidazole-4,5-dicarbaldehyde
作者:Roy K. Bowman、Andrew D. Brown、Jannine H. Cobb、John F. Eaddy、Mark A. Hatcher、Martin R. Leivers、John F. Miller、Mark B. Mitchell、Daniel E. Patterson、Matthew A. Toczko、Shiping Xie
DOI:10.1021/jo4014595
日期:2013.12.6
A robust convergent synthesis of the prodrugs of HCV replicase inhibitors 1-5 is described. The central 5H-imidazo[4,S-d]pyridazine core was formed from acid-catalyzed cyclocondensation of an imidazole-4,5-dicarbaldehyde (20) and a alpha-hydrazino ester, generated in situ from the bis-BOC-protected precursors 25 and 33. The acidic conditions not only released the otherwise unstable alpha-hydrazino esters but also were the key to avoid facile decarboxylation to the parent drugs from the carboxylic ester prodrugs 1-5. The bis-BOC alpha-hydrazino esters 25 and 33 were prepared by addition of ester enolates (from 23 and 32) to di-tert-butyl azodicarboxylate via catalysis with mild inorganic bases, such as Li2CO3. A selective aerobic oxidation with catalytic 5% Pt-Bi/C in aqueous KOH was developed to provide the dicarbaldehyde 20 from the diol 27.