New transformations of N-hetarylcyclopentano[d][1,2,3]triazoline ring into 5-alkoxyvaleramidines

It was found that brief refluxing of N-hetarylcyclopentano[d][1,2,3]triazolines in methanol resulted in the elimination of nitrogen, accompanied by cyclopentane ring opening with the formation of N-hetarylvaleramidines. Amidines containing pyrimidine-2,4-dione ring were synthesized by a one-step procedure – the reaction of 5-azidopyrimidine-2,4-diones with endocyclic enamines containing a cyclopentene ring proceeded through an N-pyrimidyl-1,2,3-triazoline intermediate. Triazolines containing a 1,3,5-triazine ring at position 1 did not form valeramidines upon refluxing in methanol. N-(1,3,5-triazin-2-yl)cyclopenta[d][1,2,3]triazoline containing a morpholine ring at position 6a underwent a different type of transformation upon dissolving in acetic acid, resulting in the formation of N-(1,3,5-triazin-2-yl)diaminoalkene. Mechanisms for these transformations are proposed.