Synthesis of the 2- and 4-monomethyl ethers and the 4-deoxy-4-fluoro derivative of 4-cyanophenyl 1,5-dithio-β- d-xylopyranoside as potential antithrombotic agents

Abstract

The title glycoside undergoes acetonation with 2-methoxypropene to give a 2:1 mixture of the crystalline 2,3- and 3,4-isopropylidene acetals in 94% yield, which upon methylation under controlled conditions followed by deacetonation afforded the respective 4- and 2-monomethyl ethers. The 2,3-acetal underwent reaction with diethylaminosulfur trifluoride to introduce fluorine at C-4 with net retention of stereochemistry, but the 3,4-acetal under comparable conditions underwent migration of the arylthio group to C-2 and fluorination at C-1, with stereochemical retention at both positions.