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Differentiation of isomeric 5- and 7-oxo derivatives of tetrahydrothiazolo[3,2-a]pyrimidine by electron impact mass spectrometry

✍ Scribed by Edwige Jeanneau-Nicolle; Claude Bosso; Martine Benoit-Guyod; Gérard Leclerc

Publisher
John Wiley and Sons
Year
1993
Tongue
English
Weight
319 KB
Volume
28
Category
Article
ISSN
1076-5174

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✦ Synopsis

The electron impact mass spectra of two series of 5-oxo-te~hydro-SH-tlriPzolo13,hl pyrimidine+ etbylcarboxylates and 7sxo-tetrahyBro-7H-thirzolo[ 3 , k l pyrimidine-6-ethykarboxylates were measured and fragmentation patterns examined. Structures were assigned from analysis of 0x0 molecular ion fragmentations.

Compounds of the 50x0 series gave an [ M -CO,CIH, I + fragmentation whereas compounds of the 7 -0 ~0 series gave three characteristic cleavages. This decomposition was coRfirmed for one pair of isomers by high-msolution mass spectrometry a d Imimokcular mass-analysed ion kinetic energy spectrometry. Electron imgnct m a s spectrometry is a convenient method for assigning structures of 5-and 7 -0 ~0 regioisowrs of tetrahydrothiazolo [ 3 , s u ] pyrimidine-6-carboxyhtes

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