Abstract Bis (trimethylsilyl) derivative of ethyl 3-aminopyrazole-4-carboxylate (VI) and tris (trimethylsilyl) derivative of ethyl 3, 5-diaminopyrazole-4-carboxylate (VII) on reaction with 2, 3, 5-tri-O-benzoyl-D-ribofuranolyl chloride and subsequent debenzoylation afforded the respective β-D-ribofuranosyl derivatives VIIIa and Xa. Their alkaline hydrolysis led to 1-(β-D- ribofuranosyl)-3-aminopyrazole-4-carboxylic acid (VIIIc) and 1-(β-D-ribofuranosyl)-3, 5- ...