Syntheses of 1, 1-Disubstituted-3-aminoguanidines

The reaction of S-methyl-isothiosemicarbazide hydriodide with morpholine or pyrrolidine gave the corresponding new 1, 1-disubstituted-3-aminoguanidines in good yields, but the yield was poor in the case of piperidine. Therefore the reaction of cyanopiperidine with hydrazine was attempted. This reaction required considerably prolonged reaction time, and the yield was not improved.The reactivity of pyrrolidine, morpholine and piperidine with S-methyl-isothiosemicarbazide to give the corresponding 1, 1-disubstituted-3-aminoguanidines decreased in the order named, whereas the order of reactivity was pyrrolidine>piperidine> morpholine in the case of the reaction with S-methylisothiourea. These results suggest that the reaction mechanism may be somewhat different between these two reactions.