合成路线1

The synthesis of selenazole is as follows: 2,3,5-Tri-O-benzoyl-beta-D-ribofuranosyl-1-carbonitrile (I) is treated with liquid hydrogen selenide, using 4-(dimethylamino)pyridine as a catalyst, under nitrogen at room temperature to give 2,5-anhydro-3,4,6-tri-O-benzoyl-D-allonselenenoamide (II). (II) is treated, in acetonitrile, with ethyl bromopyruvate. After an hour the solvent is removed in vacuo and the residue triturated with sodium bicarbonate and extracted with ethyl ether. After workup to remove the ether, chromatographic separation of the alpha- and beta-anomers on silica gel gives ethyl 2-(2,3,5-tri-O-benzoyl-beta-D-ribofuranosyl)selenazole-4-carboxylate (III). Compound (III) is dissolved in methanol and treated with ammonia at 0 C. After 48 h the solvent is removed, the residue extracted with chloroform, the chloroform layer discarded and the residue chromatographed on silica gel. Recrystallization of the major product from 2-propanol yields crystalline 2-beta-D-ribofuranosylselenazole-4-carboxamide. The preparation of the 5'-phosphate derivative is also described.