Ec. Taylor et al., PROTECTION AND DEPROTECTION OF FUSED 2-AMINO-4(3H)-PYRIMIDINONES - CONVERSION OF PTERINS AND 5-DEAZAPTERINS TO 2,4-DIAMINO DERIVATIVES, Heterocycles, 36(8), 1993, pp. 1883-1895
5-Deazapterins and pterins are readily converted to their 4-deoxy-4-am
ino derivatives (a lactam-to-amidine conversion) by reaction with 4-ch
lorophenyl phosphorodichloridate and 1,2,4-triazole to give intermedia
te 4-[1'-(1,2,4-triazolyl)] derivatives, followed by reaction with aqu
eous ammonia. Some anomalous results obtained by application of the Mi
tsunobu reaction (normally a lactam-to-lactim ether conversion) to 5-d
eazapterins are detailed.