A short protocol for the conversion of the 2-chloro-9-(2-deoxy-2-fluoro-β-d-arabinofuranosyl) hypoxanthine to 9-(2-deoxy-2-fluoro-β-d-arabinofuranosyl) guanine (araf-g)

The current protocol was aimed to describe step by step synthesis of 9-(2-deoxy-2-fluoro-β-D-arabinofuranosyl) guanine from 2-chloro-9-(2-deoxy-2-fluoro-β-D-arabinofuranosyl) hypoxanthine as masked guanine precursor. The method described here is straight forward coupling of 3, 5-di-O-benzoyl-2-deoxy-2-fluoro-α-D-arabinofuranosyl bromide 1(Elzagheid et al., 2002)with a silylated 2-chlorohypoxanthine base 2(Elzagheid et al., 2003).Subsequent treatment of N9-glycoside 3 with methanolic ammonia (150oC, 6 h) afforded 9-(2-deoxy-2-fluoro-β-D-arabinofuranosyl) guanine 4 in more than 60%yield. This procedure can be applied in large scale synthesis of this nucleoside.