Nathan W Fenwick, Amie Saidykhan, Yasser Nazir, Richard Telford, Binyaameen Masood, William H C Martin, Richard T Gallagher, Richard D Bowen
{"title":"苯甲酰苯胺质谱中的邻近效应。","authors":"Nathan W Fenwick, Amie Saidykhan, Yasser Nazir, Richard Telford, Binyaameen Masood, William H C Martin, Richard T Gallagher, Richard D Bowen","doi":"10.1177/14690667211054152","DOIUrl":null,"url":null,"abstract":"<p><p>The analytical value of peaks arising by a proximity effect in the electron ionization mass spectra of benzanilides has been established by examining the spectra of numerous examples of general structure XC<sub>6</sub>H<sub>4</sub>NHCOC<sub>6</sub>H<sub>4</sub>Y. Significant [M-X]<sup>+</sup> signals are observed only when X = Cl, Br, I or CH<sub>3</sub>O in the 2-position. The presence of strong [M-X]<sup>+</sup> signals, but negligibly weak [M-Y]<sup>+</sup> peaks, even when the C-Y bond would be expected to break more readily than the C-X bond, indicates that these diagnostically useful signals do not arise by simple cleavage. Similarly, the presence of an appreciable [M-Cl]<sup>+</sup> signal, but no [M-Br]<sup>+</sup> signal, in the spectra of representative examples of 4-Br-2ClC<sub>6</sub>H<sub>3</sub>NHCOC<sub>6</sub>H<sub>4</sub>Y, reveals that loss of a substituent from the 2-position occurs much more rapidly than fission of a weaker bond to a substituent in the 4-position. These trends are interpreted in terms of cyclization of the ionized 2-substituted benzanilide, followed by elimination of the substituent originally in the 2-position, to form a protonated 2-arylbenzoxazole.</p>","PeriodicalId":12007,"journal":{"name":"European Journal of Mass Spectrometry","volume":null,"pages":null},"PeriodicalIF":1.1000,"publicationDate":"2021-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ftp.ncbi.nlm.nih.gov/pub/pmc/oa_pdf/b1/ba/10.1177_14690667211054152.PMC8586190.pdf","citationCount":"1","resultStr":"{\"title\":\"Proximity Effects in Mass Spectra of Benzanilides.\",\"authors\":\"Nathan W Fenwick, Amie Saidykhan, Yasser Nazir, Richard Telford, Binyaameen Masood, William H C Martin, Richard T Gallagher, Richard D Bowen\",\"doi\":\"10.1177/14690667211054152\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p><p>The analytical value of peaks arising by a proximity effect in the electron ionization mass spectra of benzanilides has been established by examining the spectra of numerous examples of general structure XC<sub>6</sub>H<sub>4</sub>NHCOC<sub>6</sub>H<sub>4</sub>Y. Significant [M-X]<sup>+</sup> signals are observed only when X = Cl, Br, I or CH<sub>3</sub>O in the 2-position. The presence of strong [M-X]<sup>+</sup> signals, but negligibly weak [M-Y]<sup>+</sup> peaks, even when the C-Y bond would be expected to break more readily than the C-X bond, indicates that these diagnostically useful signals do not arise by simple cleavage. Similarly, the presence of an appreciable [M-Cl]<sup>+</sup> signal, but no [M-Br]<sup>+</sup> signal, in the spectra of representative examples of 4-Br-2ClC<sub>6</sub>H<sub>3</sub>NHCOC<sub>6</sub>H<sub>4</sub>Y, reveals that loss of a substituent from the 2-position occurs much more rapidly than fission of a weaker bond to a substituent in the 4-position. These trends are interpreted in terms of cyclization of the ionized 2-substituted benzanilide, followed by elimination of the substituent originally in the 2-position, to form a protonated 2-arylbenzoxazole.</p>\",\"PeriodicalId\":12007,\"journal\":{\"name\":\"European Journal of Mass Spectrometry\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":1.1000,\"publicationDate\":\"2021-10-01\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"https://ftp.ncbi.nlm.nih.gov/pub/pmc/oa_pdf/b1/ba/10.1177_14690667211054152.PMC8586190.pdf\",\"citationCount\":\"1\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"European Journal of Mass Spectrometry\",\"FirstCategoryId\":\"92\",\"ListUrlMain\":\"https://doi.org/10.1177/14690667211054152\",\"RegionNum\":4,\"RegionCategory\":\"化学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q4\",\"JCRName\":\"PHYSICS, ATOMIC, MOLECULAR & CHEMICAL\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"European Journal of Mass Spectrometry","FirstCategoryId":"92","ListUrlMain":"https://doi.org/10.1177/14690667211054152","RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"PHYSICS, ATOMIC, MOLECULAR & CHEMICAL","Score":null,"Total":0}
Proximity Effects in Mass Spectra of Benzanilides.
The analytical value of peaks arising by a proximity effect in the electron ionization mass spectra of benzanilides has been established by examining the spectra of numerous examples of general structure XC6H4NHCOC6H4Y. Significant [M-X]+ signals are observed only when X = Cl, Br, I or CH3O in the 2-position. The presence of strong [M-X]+ signals, but negligibly weak [M-Y]+ peaks, even when the C-Y bond would be expected to break more readily than the C-X bond, indicates that these diagnostically useful signals do not arise by simple cleavage. Similarly, the presence of an appreciable [M-Cl]+ signal, but no [M-Br]+ signal, in the spectra of representative examples of 4-Br-2ClC6H3NHCOC6H4Y, reveals that loss of a substituent from the 2-position occurs much more rapidly than fission of a weaker bond to a substituent in the 4-position. These trends are interpreted in terms of cyclization of the ionized 2-substituted benzanilide, followed by elimination of the substituent originally in the 2-position, to form a protonated 2-arylbenzoxazole.
期刊介绍:
JMS - European Journal of Mass Spectrometry, is a peer-reviewed journal, devoted to the publication of innovative research in mass spectrometry. Articles in the journal come from proteomics, metabolomics, petroleomics and other areas developing under the umbrella of the “omic revolution”.