ortho-dimethoxy effect in the Chichibabin reaction

A phenomenon, called the o-dimethoxy effect, was detected and consists in the fact that, in the sodium amide with aromatic and heterocyclic compounds with an o-dimethoxy grouping, one of the methoxy groups undergoes demethylation to form the corresponding o-methoxyphenol. The formation of an o-methoxyphenoxide anion in the case of N-heteroaromatic compounds hinders their animation by sodium amide. Compounds with m- and p-dimethoxy groups readily undergo the Chichibabin reaction. It is assumed that the nature of the o-dimethoxy effect is associated with sorption factors that are substantial for heterogeneous reactions such as the Chichibabin reaction.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1105–1111, August, 1971.The authors sincerely thank Professor L. N. Yakhontov and Candidate of Chemical Sciences V. A. Azimov for their assistance in the chromatographic determination of the gases.