The insertion of a 5-allyl, a prop-2-ynyl, or a prop-1-ynyl substituent into 1, 2-dihydro-2-imino- 1, 4, 6-trimethyl-pyrimidine progressively decreases the basic strength and increases the rate of Dimroth rearrangement into the corresponding 4, 6-dimethyl-2- methylaminopyrimidine; similar effects follow replacement of the 1-methyl group in the same imine by such substituents. Condensation of 3-(prop-2-ynyl) acetylacetone with guanidine ...
