[Hydrogenated and cyclohomologous derivatives of phenothiazine. Synthesis and pharmacological activity of various cycloalkyl derivatives of 4H-benzo(b)(1,4)thiazine].

The synthesis and the results of pharmacological screening of 4H-benzo[b][1,4]thiazine derivatives are described. These substances were prepared by reacting 2,2'-dithiodianiline with ethyl-2-oxocycloalkanecarboxylates followed by NaBH4 reduction. The pharmacological results indicate remarkable depressive activity [see (IV b) (n = 3)] shown by 100% potentiation of barbituric-induced sleeping time.