Synthesis of 8-methyl-6-thio-7-(β-D-xylopyranosyl)theophylline. Conformational study of its peracetyl derivatives. Molecular mechanics calculations and minimum-energy geometries of 8-methyl-7-(2′,3′,4′-tri-O-acetyl-β-D-xylopyranosyl)theophylline and 8-methyl-6-thio-7-(2′,3′,4′-tri-O-acetyl-β-D-xylopyranosyl)theophylline

Abstract

The synthesis of a thioxanthine nucleoside, 8-methyl-6-thio-7-(β-D-xylopyranosyl)theophylline, is reported. The triacetyl derivatives, 3 and 4, exhibit major molecular crowding and restricted rotation about the glycoside bond. The stability of the rotamers and the syn–anti equilibrium were studied by molecular mechanics. The results obtained were quite consistent with those provided by the line-shape method.