2-Amino-8-(2-deoxy-2-fluoro-β-D-arabinofuranosyl)imidazo[1,2-a]-1,3,5-triazin-4(8H)-one: Synthesis and Conformation of a 5-Aza-7-deazaguanine Fluoronucleoside

✍ Scribed by Virginie Glaçon; Frank Seela

• Publisher: John Wiley and Sons
• Year: 2004
• Tongue: German
• Weight: 112 KB
• Volume: 87
• Category: Article
• ISSN: 0018-019X
• DOI: 10.1002/hlca.200490113

✦ Synopsis

Abstract

Nucleobase‐anion glycosylation of 2‐[(2‐methyl‐1‐oxopropyl)amino]imidazo[1,2‐a]‐1,3,5‐triazin‐4(8__H__)‐one (6) with 3,5‐di‐O‐benzoyl‐2‐deoxy‐2‐fluoro‐α‐D‐arabinofuranosyl bromide (8) furnishes a mixture of the benzoyl‐protected anomeric 2‐amino‐8‐(2‐deoxy‐2‐fluoro‐D‐arabinofuranosyl)imidazo[1,2‐a]‐1,3,5‐triazin‐4(8__H__)‐ones 9/10 in a ratio of ca. 1 : 1. After deprotection, the inseparable anomeric mixture 3/4 was silylated. The obtained 5‐O‐[(1,1‐dimethylethyl)diphenylsilyl] derivatives 11 and 12 were separated and desilylated affording the nucleoside 3 and its α‐D anomer 4. Similar to 2′‐deoxy‐2′‐fluoroarabinoguanosine, the conformation of the sugar moiety is shifted from S towards N by the fluoro substituent in arabino configuration.