[Preparation of 3,3-disubstituted-3,4-dihydro-1,2,4-benzotriazines]

A compound formerly obtained through the reduction of cyclohexanone o-nitrophenylhydrazone has been defined as cyclohexane-3-spiro-3,4-dihydro-1,2,4-benzotriazine, and its formation has been interpreted via air oxidation of a cyclic form of o-aminophenylhydrazone formed first. The extension of such a reaction to several o-nitrophenylhydrazones of aliphatic, alicyclic and arylaliphatic ketones has been investigated. Formation of 3,4-dihydro-1,2,4-benzotriazines disubstituted in position 3 happens as a general rule; yields are good so long as bulky groups or aromatic nuclei are not close to the hydrazone double bond, hindering the amino group addition either sterically or by charge dispersion. Pharmacological screening has not shown any unusual activity for these new compounds; it is suggested that the formation of dihydrobenzotriazine derivatives be used to latentiate biologically active ketones.