No abstract

A novel and mild method was established to synthesize 6-methylidene penem compounds. This method entails a MgBr(2)/Et(3)N-promoted aldol-type condensation on 6-bromopenem 12 with an appropriately substituted aldehyde to yield the intermediate acetylated bromohydrin, which was smoothly converted to the final product with simultaneous deprotection of C3 carboxylic acid ester using activated zinc dust and phosphate buffer at pH 6.5. This process provides a useful variation of C-C bond formation method for penem derivatives and also serves as a practical synthetic method to prepare 6-exomethylenepenem derivatives without racemization at the C5 position.

We discovered an orally active carbapenem, L-084, through pharmacokinetic studies on various prodrug esters of (1R,5S,6S)-). L-084 showed a strong antimicrobial activity against Gram-positive and Gramnegative bacteria and exhibited the highest intestinal absorption among synthesized prodrugs of LJC11,036.

No abstract

The process development of ethyl-(R)-3-amino-2,5-dioxopyrrolidine-3-carboxylate (2), the chiral intermediate for the manufacture of AS-3201 (1), is described. A practical and scalable Shibasaki asymmetric amination that generates the chiral quaternary center was developed and demonstrated on kilogram scale. A safe, convenient and large scale hydrogenation of the hydrazine intermediate was also developed.