A Short-Step Synthesis of Orally Active Carbapenem Antibiotic CS-834.
作者:Makoto MORI、Sadao OIDA
DOI:10.1248/cpb.48.126
日期:——
An orally bioavailable carbapenem CS-834, which is a pivaloyloxymethyl (POM) ester-type prodrug and has (R)-5-oxopyrrolidin-3-ylthio moiety at the C-2 position of the 1β-methylcarbapenem skeleton, is currently under clinical trial. We accomplished a short-step synthesis of CS-834 by using phosphorus ylide from the intramolecular Wittig-type reaction in the key step for cyclization to the bicyclic carbapenem system. The POM ester group was found to be suitable for the cyclization conditions.
Several trials were made for the syntheses of (S)-4-hydroxy-pyrrolidin-2-one ((S)-HPD) and (R)-4-mercapto-pyrrolidin-2-one ((R)-MPD), a substituent at the 2-position of the orally active carbapenem antibiotic CS-834. The latter was synthesized from prochiral dimethyl or diethyl 3-p-methoxybenzylthioglutarate using pig liver esterase technology to give monoester with an optical purity of 51-71% e.e. as a key intermediate.