263020-25-3

Upstream product

• 263020-24-2 (3S,4S)-3-[(R)-1-(tert-butyldimethylsilyloxy)ethyl]-1-[[(p-nitrobenzyl)oxy]oxalyl]-4-[(R)-1-[[(R)-2-oxopyrrolidin-4-ylthio]carbonyl]ethyl]-2-azetidinone 
• 122-52-1 triethyl phosphite 
• 176179-66-1 (3S,4S)-3-[(R)-1-(tert-butyldimethylsilyloxy)ethyl]-4-[(R)-1-[[(R)-2-oxopyrrolidin-4-ylthio]carbonyl]ethyl]-2-azetidinone 
• 93711-85-4 (2R)-2-[(2S,3S)-3-{(1R)-1-(t-butyldimethylsilyloxy)ethyl}-4-oxoazetidin-2-yl]propionic acid 

Relevant academic research and scientific papers

A short-step synthesis of orally active carbapenem antibiotic CS-834

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.