Triazines and related products. Part VIII. Potential irreversible chymotrypsin inhibitors: 3-Alkyl-1,2,3-benzotriazin-4(3H)-ones and o-azidobenzamides

o-Nitrobenzoylation of L-phenylalanine ethyl ester and L-tyrosine ethyl ester yields N-o-nitrobenzoyl derivatives. Catalytic hydrogenation of these compounds affords N-(o-aminobenzoyl)amino-acid esters which can be cyclised with nitrous acid to 3-substituted 1,2,3-benzotriazin-4(3H)-ones or converted into N-(o-azidobenzoyl)amino-acid esters with nitrous acid and sodium azide. The decomposition of the 1,2,3-benzotriazinones has been shown to proceed by both heterolytic and homolytic pathways. In contrast to the photostability of the 1,2,3-benzotriazinones, the o-azidobenzamides rapidly lose nitrogen on irradiation in methanol with a 100 W medium-pressure lamp to afford 2-methoxy-3H-azepine-3-carboxamides.