Gh. Elgemeie et Nh. Metwally, Synthesis of structurally related purines: Benzimidazo[1,2-a]pyridines, benzimidazo-[1,2-c]pyrimidines, and pyrazolo-[1,5-a]pyrimidines, MONATS CHEM, 131(7), 2000, pp. 779-785
Reactions of sodium salts of 3-hydroxymethylene-2-alkanones with 2-cyanomet
hylbenzimidazole afforded benzimidazo[1,2-a]pyridines. Analogues reactions
with 2-aminobenzimidazole and 5-aminopyrazoles afforded benzimidazo[1.2-c]p
yrimidines and pyrazolo[1,5-a]pyrimidines.