Studies on the meso, racemic, and optically active forms of 3,6-bis-[1-hydroxy-1-(4-methylphenyl)ethyl]-1,2,4,5-tetrazines and related systems along with the corresponding 3,5-disubstituted 1,2,4-triazoles, their 4-amino-derivatives and 2,5-disubstituted 1,3,4-oxadiazoles including their circular dichroism spectra

Abstract

The stereoisomeric title compounds (II)–(VI) were prepared by the action of hydrazine hydrate on (±)-, (+),-and (–)-amidinium chlorides (I). The initial products, the dihydrotetrazines (II), were readily oxidised to the tetrazines (III) or could undergo rearrangement in methanolic hydrogen chloride to give the corresponding 4-amino-1,2,4-triazoles (IV) which by deamination with nitrous acid yielded the 1,2,4-triazoles (VI). The 1,3,4-oxadiazoles (V) were most easily prepared by the action of 40% peracetic acid on the tetrazines (III), other methods tending to give diacylhydrazines (VII). A study was made of the c.d. curves of the optically active forms of compounds (II)–(VI) including studies in both acid and neutral solutions for the triazoles (IV) and (VI).