Pyrolyses and Mass Spectra of 2-Benzoxazolinone, 2-Benzimidazolinone, and 2-Benzothiazolinone

• Published in: Canadian journal of chemistry 1973-10, Vol.51 (20), p.3313-3321
• Main Authors: Thomson, Michael L, DeJongh, Don C
• Format: Article
• Language: English
• ISSN: 0008-4042; 1480-3291
• DOI: 10.1139/v73-495

The electron-impact and chemical-ionization mass spectra of 2-benzoxazolinone ( 5 ), 2-benzimidazolinone ( 6 ), and 2-benzothiazolinone ( 7 ) have been compared with their pyrolysis products and parallels have been found. In each case, loss of CO occurs from followed by loss of CO for 5 and by HCN for 6 and 7 . At 950° in a stream of N 2 , 5 gave 17% of C 5 H 5 N isomers, related to the loss of 2CO, along with 5.6% of quinoline. Compound 6 gave 14% of C 6 H 4 N 2 isomers, related to the loss of CO. At 950°, 7 gave 2-thiophenecarbonitrile (1.1%), cyanonaphthalenes (4.5%), aniline (3%), cyanobenzene (2.5%), naphthalene (1.5%), and phenylisocyanate (2.5%). From 5 - 7 20 - 70 % of the starting material was recovered or accounted for by isolation and identification of products in each case. G.c./m.s. was used to study pyrolysis mixtures.