Regioselective synthesis of N-acyl- and N-alkyldioxolo[4,5-b]phenothiazines

We describe the preparation of new substituted dioxolo [4,5-b]phenothiazines by two slightly different reaction sequences. N-Arylation of [1,3]benzodioxol-5-amine with organolead or organobismuth reagents afforded N-aryl [1, On the other hand, [1,3]benzodioxol-5-amine was first N-alkylated, the resulting Nalkyl[1,3]benzodioxol-5-amines were N-phenylated, before Bernthsen the final tetracyclic thionation furnished product.