5‐Amino‐5‐deoxyribose derivatives. Synthesis and use in the preparation of “Reversed” Nucleosides

Methyl 5‐amino‐5‐deoxy‐2,3‐ O ‐isopropylidene‐β‐D‐ribofuranoside (III) has been synthesized and used as an intermediate in the preparation of the kinetin analog, methyl 5‐deoxy‐5‐(purin‐6‐yl)amino‐β‐D‐ribofuranoside (X). The related 1‐substituted adenine, methyl 5‐ (6‐aminopurin‐1‐yl)‐5‐deoxy‐2,3‐ O ‐isopropylidene‐β‐D‐ribofuranoside (XIII), was prepared by cyclization of 1‐benzyl‐5‐cyano‐4‐ethoxymethyleneaminoimidazole (XI) with III and subsequent debenzylation with sodium in liquid ammonia. The structures and stereochemistry of these compounds were established by a combination of ultraviolet and nuclear magnetic resonance spectroscopy.