The synthesis of 1,4,7,9-tetraazabenzo[b]phenothiazine ring system from 4-aminopyrimidine is reported. This new heterocyclic ring was obtained by converting a 4-aminopyrimidine to the corresponding 5-thiocyanato derivative followed by hydrolysis and subsequent treatment with 2,3-dichloroquinoxaline. Several derivatives were obtained by using suitable substituted starting materials. Nitration with mixed nitric and sulfuric acids gave the corresponding 13-nitro derivatives. Spectral analyses are in agreement with the assigned structures.
Journal of Heterocyclic Chemistry 11/1980; 17(7):1587 – 1592. DOI:10.1002/jhet.5570170747