Reactive intermediates. Part XI. The generation and some reactions of benzynequinone
Abstract
1-Amino-4,7-dimethoxybenzotriazole is prepared in six steps from 2,5-dimethoxybenzamide. Demethylation of the former with boron tribromide, followed by oxidation with silver oxide gives 1-aminobenzotriazole-4,7-quinone which, on treatment with lead tetra-acetate yields benzynequinone, isolated as 5,6,7,8-tetraphenyl-1,4-naphthoquinone from a reaction with tetracyclone. 1-Amino-5,6-dimethoxybenzotriazole is synthesised in four steps from 4-amino-5-nitroveratrole, but attempts to isolate 1-amino-5,6-dihydroxybenzotriazole from it by demethylation have so far proved unsuccessful.
The generation of 3,6- and 4,5-dimethoxybenzyne is described.