Thio- and 2 4 -Aminobenzodiazepinium Salt

There has been interest in 2(4)-amino- and 2(4)-thio-benzodiazepines because a number of them show physiological and pharmacological activity (see also Section I). Thus, some 2-amino derivatives can behave as tranquilizers, 2-amino-4-thio derivatives show a variety of activity, some as anticonvulsants, others as stimulants, and certain 2-thio derivatives have antibacterial properties. 

A 2-acetylthiobenzodiazepine is obtained by treating the thione with acetic anhydride (75JHC825). Other variants are the use of dithietane instead of a dimercaptoenone and of diazomethane to convert the thione into a methylthio group (76T483). 

Mass spectral studies on 2-methylthio-4-phenylbenzodiazepine, which IR, NMR, and electronic spectra show to exist in the diimine form in solution, suggest that in the gas phase there is a tautomeric equilibrium between the diimine and conjugated forms (90KGS396). 

Aqueous acid hydrolyzes the alkylthio group and forms a benzodiazepine-one (73JHC875). Oxidation by hydrogen peroxide brings about a similar conversion (80H7). Treatment of N-substituted 4-(2 diethy- 

A prime role played by 2-thiobenzodiazepines has been that of convenient precursors for the preparation of a variety of 2-aminobenzodiaze-pines. The previous paragraph presented examples of the substitution of 

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