Journal article

CONCERNING THE REGIOSELECTIVITY OF GAS-PHASE REACTIONS OF GLYCINE WITH ELECTROPHILES - THE CASES OF THE DIMETHYLCHLORINIUM ION AND THE METHOXYMETHYL CATION

RAJ OHAIR, MA FREITAS, S GRONERT, JAR SCHMIDT, TD WILLIAMS

JOURNAL OF ORGANIC CHEMISTRY | AMER CHEMICAL SOC | Published : 1995

Abstract

The gas phase reactions of glycine with the dimethylchlorinium ion and the methoxymethyl cation in the Cl source of a tandem mass spectrometer have been investigated. The mechanisms of these reactions were determined by analyzing the unimolecular fragmentation reactions of the product ions. (CH3)2C1+ undergoes a nonregioselective Sn2 reaction, with methylation occurring at both nitrogen and oxygen. This is consistent with the relative methyl cation affinities (MCAs) of CH3CI (MCA (CH3CI) = 62.0 kcal mol-1) and those calculated via ab initio calculations (at the MP2/6-31G*//HF/6-31G* level) for the three nucleophilic sites in glycine: MCA (H2N group) = 116.0 kcal mol-1, MCA (C=0 group) = 90.8..

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University of Melbourne Researchers