122604-89-1Relevant articles and documents
Synthesis of Nitrogen-Containing Heterocycles. II. Cyclization of Diaminomethylenehydrazones with Ethoxymethylene Compounds
Miyamoto, Yoshiko,Kobana, Richiko,Yamazaki, Chiji
, p. 1963 - 1969 (2007/10/02)
Condensation of diaminomethylenehydrazones (1) with ethyl ethoxymethylenecyanoacetate (2) gave amino(substituted vinylamino)methylenehydrazones (3) in high yields.Amino(monomethylamino)methylenehydrazones were more reactive than amino(dimethylamino)methylenehydrazones and, when the reaction temperature was raised, with or without addition of a base, directly produced 2,3-dihydro- or 2,3-dehydrotriazolopyrimidine-8-carboxylates, depending upon the carbonyl component of the diaminomethylenehydrazone.Ketone amino(dimethylamino)methylenehydrazone gave no cyclized product.Similar condensation of diaminomethylenehydrazones with diethyl ethoxymethylenemalonate gave the linear products (7) and, when R2 was hydrogen, the intermediate cyclized to dihydro-4-oxopyrimidinecarboxylate by exclusive intramolecular attack of N(4) on the ethoxycarbonyl carbon. diaminomethylenehydrazone; ethyl ethoxymethylenecyanoacetate; diethyl ethoxymethylenemalonate; amino(substituted vinylamino)methylenehydrazone; triazolopyrimidine-8-carboxylate; dihydro-4-oxopyrimidine
