Effect of the N-Phenyl Substituent on the Pyrolyses of 1-Phenyl-2-benzothiazolinone and 1-Phenyl-2-benzothiazolinethione

Abstract

Results from the pyrolyses of 1-phenyl-2-benzothiazolinone (7) and 1-phenyl-2-benzothiazolinethione (8) are reported and compared with those obtained previously from the corresponding compounds without the N-phenyl group. The mass spectra of 7 and 8 are reported, also. The major fragmentation in the mass spectrum of 7 is the loss of CO, followed by loss of S or H. Pyrolysis of 7 at 750° in a stream of nitrogen gives phenothiazine (9, 31%) and carbazole (10, 28%), by loss of CO and of CO and S, respectively. Pyrolysis of 9 yields 10. The major fragmentation in the mass spectrum of 8 is the loss of H. Pyrolysis of 8 at 750° produces 2-(phenylthio)benzothiazole (11, 87%), which is an isomer of 8, resulting from phenyl migration, and 2-phenylbenzothiazole (12, 3%). Pyrolysis of 11 gives 12.