Preparation of tricyclic imidazopyridines by asymmetric ketone hydrogenation in the presence of RuCl2[(S)-Xyl-P-Phos][(S)-DAIPEN]
摘要:
The novel complex RuCl2[(S)-Xyl-P-Phos][(S)-DAIPEN] was identified as a highly active catalyst for the asymmetric reduction of a variety of prochiral ketones possessing an imidazo[1,2-a]pyridine scaffold. The corresponding alcohols were obtained in excellent enantiomeric purities (>96% ee) and served as valuable intermediates for the synthesis of pharmacologically active 7H-8,9-dihydropyrano[2,3-c]imidazo[ 1,2-alpyridines. The complexity of these multi-functional substrates required the development of specific reaction conditions. Whereas the reduction with RuCl2[PP][NN] catalysts (Noyori catalysts) has never been reported to occur under aqueous conditions, in the present case, the use of aqueous isopropanol or tert-butanol was not only tolerated, but also turned out to be beneficial, especially when the reduction was conducted at high substrate to catalyst (S/C) ratios. (C) 2008 Elsevier Ltd. All rights reserved.
[EN] PROCESS FOR THE PRODUCTION OF INTERMEDIATES FOR THE PREPARATION OF TRICYCLIC IMIDAZOPYRIDINES<br/>[FR] PROCÉDÉ DE PRODUCTION D'INTERMÉDIAIRES POUR LA PRÉPARATION D'IMIDAZOPYRIDINES TRICYCLIQUES
申请人:NYCOMED GMBH
公开号:WO2007141253A1
公开(公告)日:2007-12-13
[EN] The invention relates to a process for the synthesis of compounds of the formula (1-a) and compounds of the formula (1-b). The compounds of the formula 1-a and the compounds of the formula 1-b, in which the substituents R1, R2, R3, and Arom have the meanings indicated in the description, are valuable intermediates for the preparation of pharmaceutically active compounds. [FR] La présente invention concerne un procédé de synthèse de composés répondant à la formule (1-a) et de composés répondant à la formule (1-b). Les composés de la formule 1-a et les composés de la formule 1-b, les substituants R1, R2, R3 et Arom étant tels que définis dans la description, sont des intermédiaires utiles pour la préparation de composés pharmaceutiquement actifs.
Preparation of tricyclic imidazopyridines by asymmetric ketone hydrogenation in the presence of RuCl2[(S)-Xyl-P-Phos][(S)-DAIPEN]
作者:Andreas Marc Palmer、Antonio Zanotti-Gerosa、Hans Nedden
DOI:10.1016/j.tetasy.2008.05.013
日期:2008.6
The novel complex RuCl2[(S)-Xyl-P-Phos][(S)-DAIPEN] was identified as a highly active catalyst for the asymmetric reduction of a variety of prochiral ketones possessing an imidazo[1,2-a]pyridine scaffold. The corresponding alcohols were obtained in excellent enantiomeric purities (>96% ee) and served as valuable intermediates for the synthesis of pharmacologically active 7H-8,9-dihydropyrano[2,3-c]imidazo[ 1,2-alpyridines. The complexity of these multi-functional substrates required the development of specific reaction conditions. Whereas the reduction with RuCl2[PP][NN] catalysts (Noyori catalysts) has never been reported to occur under aqueous conditions, in the present case, the use of aqueous isopropanol or tert-butanol was not only tolerated, but also turned out to be beneficial, especially when the reduction was conducted at high substrate to catalyst (S/C) ratios. (C) 2008 Elsevier Ltd. All rights reserved.