The Fragmentation of 5- and 3-Substituted Thiophene-2-carboxamides Under Electron Impact

Article abstract of DOI:10.1002/oms.1210151207

The 70 eV electron impact mass spectra of twelve 5- and 3-substituted thiophene-2-carboxamides are discussed with the aid of exact mass measurements and labelling experiments.All mass spectra exhibit pronounced molecular ions.Some isomeric 5- and 3-substituted title compounds can be differentiated by mass spectrometry.The fragmentation is influenced by a strong 'ortho-effect' which activates the NH3 elimination.In the other cases the most important fragmentation is NH2^. loss, followed by CO elimination.