Tandem cleavage of 2,3,5-trimethyl 7-trifluoroacetyl-1,2,3,4-tetrahydro-pyrrolo[1,2-c]pyrimidine by activated alkynes, caused by Michael addition of a tertiary nitrogen atom to a triple bond

The interaction of 7-trifluoroacetyltetrahydropyrrolo[1,2-c]pyrimidine with acetylenedicarboxylic ester (DMAD) and ethyl propiolate in acetonitrile and alcohols has been studied. It was established that DMAD splits pyrrolopyrimidine at the aminal fragment in acetonitrile and methanol with the formation of 1-H-and 2-(N-dimethoxycarbonylvinyl-N-methyl)aminoethyl-1-methoxymethyl-3-methyl-5-trifluoroacetylpyrroles. In acetonitrile ethyl propiolate splits pyrrolopyrimidine both at the aminal fragment and at the C(3)-N(2) bond (Hofmann reaction), but in ethanol only at the C(3)-N(2) bond with the formation of 2-propenylpyrroles.