Reactions of Per-O-Acetylglucosyl Isothiocyanate with Enamines. A Route for the Synthesis of Pyrimidine Nucleosides

Abstract

The reaction of 2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl isothiocyanate with enamines in basic medium to form the glucosylthioamides 9-16, the glucosylthiourea 17, and the nucleoside analogue 18 is reported. The N-halogenophenyl-(1-3, 5-7) and the N-(3,4-dimethoxybenzyl)-(4,8) enaminoesters or enaminones were prepared as precursors for 9-18. The treatment of several of the prepared glucosylthioamides with thiophosgene yields dithioxopyrimidine nucleosides (19-22) with the sugar ring on position 3 of the heterocycle. Glucosylamides are isolated as byproducts. The enamino moieties of the prepared glucosylthioamides and glycosylamides have the EEE configuration and the thioamide or amide bond the Z, anti geometry.