Annelation of pyrrolo[1,2-a]pyrimidine and pyrido[1,2-a]pyrimidine systems to a pyrazolopyridine framework by a cascade of two cyclization reactions

Novel fused pyrrolo[1,2-c]pyrimidines and pyrido[1,2-a]pyrimidine derivatives were prepared by a cascade of two cyclization reactions between pyrazolopyridinediamines 4 and omega-chloroketones 5-7 in ethanol as solvent and a catalytic amount of acetic acid. This approach provided the title compounds 8-10 in good yields and under mild simple one-step reaction conditions. The structures of the new compounds were unambiguously established by spectroscopic and analytical techniques. (C) 2015 Elsevier Ltd. All rights reserved.