Electron impact induced fragmentation of some 1-substituted trans-2-phenylcyclopropane compounds.

The electron impact induced fragmentation of seven derivatives of trans-2-phenylcyclopropane substituted at position one with functional groups like amino (tranylcypromine), trifluoroacetamido, cyano, carboxylic acid, carboxylic acid chloride, carboxamide and carboxylate methyl ester was investigated. Mechanisms are proposed for the formation of the major ions of each compound. The nature of the substituent determined the relative abundances of [M]+˙, [M-1]+, [M-R]+, [M-RH]+˙, [M-C6H5]+ and m/z 115 ions. A molecular ion was present in all spectra except that of carboxylic acid chloride substituted compound. In most cases, metastable peaks are involved in the decomposition of the most abundant ions. An interesting elimination mechanism involving the opening of the cyclopropane ring to yield a 4-membered cyclic ion at m/z 56 was obtained in the spectrum of trans-1-amino-2-phenylcyclopropane. All the above compounds gave mass spectra containing diagnostic fragment ions which are of great value for identification purposes.