Stereospecific synthesis of N-tosyl derivatives of dihydroconduramine E-2 and ent-F-2

Abstract

Conduramines, dihydroconduramines and structurally related compounds belong to an important class of glycosidase inhibitors which are essential elements of many biologically active compounds. The synthesis and characterization of N-tosyl dihydroconduramine derivatives 9a and 10a starting from cyclohexadiene were carried out in the current study. The oxazolidinone 15 was prepared by the palladium-catalyzed reaction of bis-carbamate 14, synthesized from cyclohexenediol, derived in two steps from cyclohexadiene. Hydrolysis of 15 was achieved with methanolic potassium carbonate to afford 18 and the ketalization gave 21 in good yield. Osmylation of the double bond and acid-mediated acetonide removal of 21 gave 4-methyl-N-((1S, 2R, 3S, 6S)-2,3,6-trihydroxycyclohexyl) benzenesulfonamide 9a. The epoxidation of 21 followed by acid-mediated epoxide ring opening and subsequent acetonide removal produced 4-methyl-N-((1S,2R,3R,6S)-2,3,6-trihydroxycyclohexyl) benzenesulfonamide 10a. The molecules may be evaluated for biological activity.