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Der massenspektrometrische Zerfall isomerer Diacetamido‐cyclo‐hexane, ihrer N ‐Phenäthyl‐Derivate und Bis (acetamidomethyl)cyclohexane. 32. Mitteilung über massenspektrometrische Untersuchungen , ,
Author(s) -
Süess Hans,
Hesse Manfred
Publication year - 1979
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19790620414
Subject(s) - chemistry , stereospecificity , cyclohexanes , cyclohexane , mass spectrum , medicinal chemistry , stereochemistry , fragmentation (computing) , polyatomic ion , ion , organic chemistry , computer science , operating system , catalysis
The Mass Spectral Decomposition of Isomeric Diacetamido‐cyclohexanes, their N ‐Phenethyl‐Derivatives and Bis(acetamidomethyl)cyclohexanes In the mass spectra of the six isomeric diacetamidocyclohexanes 2‐‐4 ( cis and trans each, Scheme 2 ) as well as of the six isomeric bis(acetamidomethyl)cyclohexanes 6‐‐8 ( cis and trans each, Scheme 5 ) are clear differences between the constitutional isomers, whereas cis/trans isomers show very similar spectra. The lack of stereospecific fragmentations is explained by loss of configurational integrity of the molecular ion before fragmentation. However, the mass spectral fragmentation of epimeric diamidocyclohexanes becomes very stereospecific by the introduction of a phenethyl group on one of the nitrogen atoms: this group avoids epimerization of the molecular ion prior to fragmentation. In the N ‐phenethyl derivatives 10, 11, 13 and 14 ( Scheme 8 ) the typical fragmentations of the cis ‐isomer after loss of ·C 7 H 7 from the molecular ion are the elimination of CH 2 CO by formation of cyclic ions, and the loss of p ‐toluenesulfonic acid or benzoic acid, respectively, with subsequent elimination of CH 3 CN ( Scheme 9 ). In the trans ‐isomer the typical fragmentations are the loss of the side chain bearing a tertiary nitrogen atom, and the elimination of the tosyl or benzoyl radical, respectively, with subsequent loss of CH 3 CONH 2 ( Scheme 10 ).