Deazapurine derivatives. V: A new synthesis of 1‐ and 3‐deaza‐adenine and related compounds

Abstract

Abstract Reinvestigation of the cyclization of 2,3,4‐triaminopyridine (1) by several procedures showed that both 7‐aminoimidazo[4,5‐ b ]pyridine (1‐deaza‐adenine, II) and 4‐aminoimidazo[4,5‐ c ]pyridine (3‐deaza‐adenine, III) were always obtained. A new and convenient route to the synthesis of II has been devised. Also an unambiguous synthesis of III is given. Ring closure of 2,4,5‐triamino‐pyridine (XIX) afforded 6‐aminoimidazo[4,5‐c]pyridine (3‐deazaisoadenine, XX).