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Mechanisms of decarboxylation of ortho-substituted benzoic acids

2006; Elsevier BV; Volume: 807; Issue: 1-3 Linguagem: Inglês

10.1016/j.theochem.2006.12.004

1872-7999

Krum Chuchev, Joseph J. BelBruno,

Advanced Chemical Physics Studies

The rotational transition state in the isomerization of the syn- to anti-conformer for the parent and substituted benzoic acids has been characterized and the decarboxylation mechanism for these acids has been determined. A previously unreported intermediate in the salicylic acid decarboxylation pathway has been observed, demonstrating that there is a change in the reaction mechanism when the ortho-group participates in the development of the transition state. The intermediate, in a shallow well, has a keto-like structure. While salicylic acid reacts through the keto-like intermediate, other substituted benzoic acids, including 2-aminobenzoic acid, follow the previously reported direct mechanism.