Synthesis and X-Ray Crystal Structure of 2-β-D-Ribofuranosylthiazole-4-Carboxamide-N₃-Oxide

Abstract

2-β-D-Ribofuranosylthiazole-4-carboxamide-N₃-oxide (3) has been prepared by oxidation of tiazofurin (2) with hydrogen peroxide in the presence of trifluoroacetic acid. The absolute structure of 3 has been determined by X-ray diffraction techniques employing Mo Kα radiation. The thiazole ring in 3 is planar and the glycon moiety is in the ³E configuration. The N3-C4 bond in 3 is significantly larger (1.412 Å) than that found in tiazofurin (1.376 Å). Similar to tiazofurin, the S…04’ intramolecular contact distance is considerably shorter than the sum of the van der Waals radii, which favors the anti conformation of 3.