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

Abstract

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 M t , followed by loss of C O for 5 and by H C N for 6 and 7. At 950" in a stream of N,, 5 gave 17% of C,H,N isomers, related to the loss of 2C0, along with 5.6% of quinoline. Compound 6gave 14% of C6H,N, isomers, related to the loss of CO. At 950°, 7 gave 2-thiophenecarbonitrile (1 .I%), cyanonaphthalenes (4.5%), sniline (373, 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.1m.s. was used t o study pyrolysis mixtures.On rapporte les spectres de masse de la benzoxazolinone-2 (5), de la benzimidazolinone-2 (6) e t de la benzothiazolinone-2 (7). tels qu'obtenus par impact tlectronique et par ionisation chimique en utilisant I'isobutane. On compare ces spectres avec les produits de pyrolyse des coniposCs 5-7. Dans chaque cas, l'ion molCculaire elimine une molecule de CO. Pour les composCs 6 et 7, ce processus est suivi d'une elimination de HCN, alors que pour le compose 5, il est suivi de la perte d'une deuxieme molCcule d e CO.La pyrolyse du compost 5 a 950" dans un courant d'azote conduit a la formation de quinoline (5.6%) et d'isomeres repondant a la formule C5H,N, ces derniers a la suite de I'elimination de deux molecules de CO. Parallelement, le compose 6 donne des isomeres repondant a la formule C5H,N, ces derniers a la suite de I'Climination de deux molCcules de CO. Parallelement, le compose 6 donne des isomeres rdpondant a la formule C6H,N, par elimination d'une molCcule de C O et d'une molecule de HZ. Les produits de la pyrolyse du compose 7 a 950" sont le thiophknecarbonitrile-2 (1.1%), les cyanonaphthalenes (4.5%), I'aniline (373, le cyanobenzene (2.5%), le naphthalene (1.5%) et I'isocyanate de phenyle (2.5%). Les produits form& ainsi que les produits originaux rCcupCrCs representent de 20 a 70% des produits de depart. La combinaison de la chromatographie en phase gazeuse avec la spectrometrie de masse etait employee pour Ctudier les melanges obtenus des pyrolyses.

Mass Spectra of 3-Methyl-2(3H)benzoxazolone Hydrazone Phosphorylated Compounds

“…The compounds studied are O,O-dimethyl (or diethyl)-3-methyl-, 2(3H)benzoxazolone hydrazone phosphates (1,2) and the corresponding thiophosphates (3,4). They are solids, which exist as white crystals with clearly defined melting points.…”

“…1,2 There has also been a very extensive study concerning N-substituted derivatives of 2-aminobenzoxazole. 3 The present paper analyses the fragmentation patterns, under electron ionization, characteristic of new hydrazono phosphorus esters, in which the unstable N-methylbenzoxazolone-hydrazone group, 4 becomes stabilized through bonding to a phosphorylic or a thiophosphorylic radical (-P(X)(OR) 2 X = O (compounds 1,2), S (compounds 3,4); R = CH 3 , C 2 H 5 ).…”

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

“…In the pyrolysis of 4 at 1000", we recovered 10.2% of starting material and we isolated 14% of C,H,N, isomers, as shown in eq. 1 (5). However, when l-phenyl-2-Can.…”

“…benzimidazolinone (5) was pyrolyzed at 950°, 16.3% of 5 was recovered and the major product isolated was phenazine (6), as shown in eq. 2 (7).…”

“…The pyrolysis of 2-benzothiazolinone (1, a = NH; b = S; c = C; d = 0) presented a special problem (5): no products were isolated that could be related to intermediate 2 (a = NH; b = S). This is probably due to the fact that sulfur is retained and the loss of CO followed by HCN gives products such as cyclopentadienethione which polymerize.…”