Electron-impact mass spectra of substituted 1-alkyl-2-arylsulphonylamino-1,4,5,6-tetrahydropyrimidines

✍ Scribed by Vladimir Ovcharenko; Elzbieta Szacon; Tadeusz Tkaczynski; Dariusz Matosiuk; Kalevi Pihlaja

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 88 KB
• Volume: 12
• Category: Article
• ISSN: 0951-4198
• DOI: 10.1002/(sici)1097-0231(19980831)12:16<1041::aid-rcm279>3.0.co;2-n

✦ Synopsis

Fragmentation pathways of the title compounds under electron impact were compared to those of their (1aryl)substituted analogs reported earlier. The main fragmentation route of the M Á ions is the sulphamide N-S bond cleavage leading to [M À ArSO 2 ] ions. No loss of the alkyl substituents from the tetrahydropyrimidine ring of M Á ions was observed, but there were abundant (b10% total ion current) peaks of [M À SO 2 À R] ions apparently formed via unstable [M À SO 2 ] Á and [M À R] species, as demonstrated by the metastable ion spectra. Fragmentation of cyclic alkylguanidinium ions [M À ArSO 2 ] involves consecutive losses of CH 2 N 2 and C 2 H 4 fragments, the former process preceding the latter. This stepwise fragmentation pattern distinguishes (1-alkyl)substituted tetrahydropyrimidines from their (1-aryl)substituted analogs, which produced comparable amounts of [M À ArSO 2 À C 2 H 4 ] and [M À ArSO 2 À CH 2 N 2 ] ions as the precursors of [M À ArSO 2 À C 3 H 6 N 2 ] ions.