On triazoles. XII. The carbamoylation and thiocarbamoylation of 5-amino-1,2,4-triazoles

The reaction of 5-amino-3-R-1H-1,2,4-triazoles 1 with isocyanates 2 (X = O) and isothiocyanates 2 (X = S) was studied. It was stated that with isocyanates 3a (X = O) type ring-carbamoylated products were formed which did not rearrange to the corresponding exo-carbamoylated derivatives 6a (X = O). On the other hand the thiocarbamoylation of derivatives 1 provided at mild conditions lead to derivatives 3a (X = S) which could be rearranged by heating to derivatives 6a (X = S). In one case the isomeric 4a (X = S) type derivative was also isolated. The comparison of the ir, uv, pmr and cmr spectra of the isomers isolated with the corresponding spectra of the carbamoylated and thiocarbamoylated 3,5-diamino-1,2,4-triazole derivatives helped to prove unequivocally the isomeric and tautomeric structure of compounds obtained giving a possibility to correct many confusions in the literature.