Syntheses of Heterocyclic Compounds involving Sulfur. II. Syntheses of 3-Tosyl-1, 2-dihydro-3H-pyrazino [3, 2, 1-kl] phenothiazine-1, 2-dione, 2-Tosyl-1, 2-dihydroimidazo [4, 5, 1-kl] phenothazine-1-one, and N, N'-Bis [tosyl (1-phenothiaziny1)] oxalamide from Reaction between 1-Tosylaminophenothiazine and Oxalyl Chloride

Abstract

Reaction of 1-tosylaminophenothiazine (IV) and oxalyl chloride gave 3-tosyl-1, 2-dihydro-3H- pyrazino [3, 2, 1-kl] phenothiazine-1, 2- dione (VI), N, N'-bis [tosyl (1-phenothiaziny1)] oxalamide (VII), and 2-tosyl-1, 2-dihydroimidazo [4, 5, 1-kl] phenothiazine-1-one (VIII).
Reduction of VI with lithium aluminum hydride afforded 1, 2-dihydro-3H-pyrazino [3, 2, 1-kl] phenothiazine (X), and a similar reaction of VIII gave IV, accompanied with ring-pened product.