Studies on some symmetrically and unsymmetrically 3,6-disubstituted 1,2-dihydro-1,2,4,5-tetrazines including their conversion into the corresponding tetrazines and 3,5-disubstituted 4-amino-1,2,4-triazoles

Abstract

A number of symmetrically 3,6-disubstituted 1,2-dihydro-1,2,4,5-tetrazines have been prepared by the action of hydrazine hydrate on (a) nitriles in the presence of sulphur or (b) amidinium chlorides. The dihydrotetrazines yield the corresponding 1,2,4,5-tetrazines by oxidation or 4-amino-1,2,4-triazoles by rearrangement. A reliable method for distinguishing between 1,2-dihydro-1,2,4,5-tetrazines and 4-amino-1,2,4-triazoles has been obtained from n.m.r. studies.