| Abstract: | Acetylenic amindines HC≈?C·(CH2)n·C(?NH)NH2 give, by condensation with β-ketoesters, pyrimidones substituted on carbon 2 by an acetylenic chain. Two types of evolution are observed when compounds are heated without any catalyst. The minor route is a cyclization by attack on a triple bond by the amidic nitrogen atom. The main reaction is a cycloaddition involving the non activated triple bond and an azadienic system, leading to non isolated tricyclic intermediates which retrocyclize to stable bicyclic compounds. |
