Synthesis and Reactions of Some New Benzo[a]phenothiazine‐3,4‐dione Derivatives

Abstract

The reaction of 2,3‐dihydro‐2,3‐epoxy‐1,4‐naphthoquinone (4) with substituted anilines furnished the corresponding benzo[fused]heterocyclic derivatives 5, 6, 6a, 6b, 7, 8. Furthermore, treatment of benzo[a]phenothiazine derivative 7 with halo compounds, namely, ethyl bromoacetate, phenacyl bromide, dibromoethane, or chloroacetone afforded ether derivatives 11, 12, 13, 14, respectively. Moreover, the reaction of 11 with o‐substituted aniline gave the corresponding benzo[a]phenothiazin‐5‐one derivatives 15, 16, 17 and benzo[d][1,3]oxazin‐4‐one18, respectively. Finally, the chromenone derivative 19 was synthesized via the reaction of ester derivative 11 with salicyaldhyde in refluxing pyridine. The newly synthesized compounds were characterized by spectroscopic measurements (IR, 1H NMR, 13C NMR, and mass spectra).