Reactivity of N1-Acylacetamidrazones towards Diethyl Acetylenedicarboxylate: Cyclization to Ethyl Pyrroleacetates and 1-Acylaminopyridones

Bernard AM;Cocco MT;CONGIU, CENZO;ONNIS, VALENTINA;Piras PP

1995-01-01

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Abstract

The reaction between N1-acylacetamidrazones (1) and diethyl acetylenedicarboxylate (2) is described. The nucleophilic addition of the β-carbon atom of 1 on the triple bond affords the non isolable intermediate (3). Depending on the reaction conditions and on the substitution pattern of the amidrazone, 3 gives rise to ethyl 5-(2-acylhydrazino)-4-(ethoxycarbonyl)-2-oxo-2H-pyrrole-3-acetates (4) and / or diethyl 1-acylamino-2-amino-1,6-dihydro-6-oxo-3,4-pyridinedicarboxylates (5).