Srinivas Gangula

Synthesis of All Enantiomerically Pure Diastereomers of Aprepitant

Syntheses of all eight enantiomerically pure diastereomers of aprepitant and assignment of absolute configuration at newly generated stereocenters by NMR and x-ray crystallographic analysis were achieved.

Novel Synthesis of Fosphenytoin: Anti-Convulsant Prodrug

Abstract A simple, new synthesis of fosphenytoin sodium 1, a prodrug, via imidate ester and employing mild reaction conditions is described.

Improved Process for Paroxetine Hydrochloride Substantially Free from Potential Impurities

Abstract An efficient process for production of paroxetine hydrochloride hemihydrate 1, a selective 5-hydroxytryptamine (serotonin) reuptake inhibitor, is described. Identification and control of potential impurities and establishment of efficient downstream workup procedures enabled us to produce paroxetine hydrochloride hemihydrate 1 efficiently. GRAPHICAL ABSTRACT

Recycling of undesired isomers of key intermediate for aprepitant

Abstract A protocol for regeneration of key intermediate of aprepitant from its undesired diastereomers is described. This work features the recycling of at least one-third of the undesired isomers (ent-6, 7 and ent-7) to desired isomer 4 as the key early intermediate for the synthesis of aprepitant 1. The key step in our strategy involves diastereomeric salt preparation.