Abstract
The kinetics and regioselectivity of methoxydebromination of some substituted pentabromobenzenes C6Br5X (X = NO2, CN, NH2, MeNH, and MeO) were studied in pyridine at 115°C. The partial rate factors (k f) were calculated for different positions of the polybrominated ring in these compounds. The effect of substituents X on methoxydebromination at themeta- andpara-positions is satisfactorily described only by the Hammett substituent constants (ρ = 2.22,r = 0.96). This allows one to conclude that direct polar conjugation of the substituents contributes only slightly to the transition state of the reaction. Theorthobromine atoms have a significant steric effect.
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Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1784–1788, September, 1995.
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Shishkin, V.N., Lapin, K.K., Shabarina, S.A. et al. Regioselectivity of methoxydebromination of substituted pentabromobenzenes C6Br5X in pyridine. Russ Chem Bull 44, 1715–1719 (1995). https://doi.org/10.1007/BF01151297
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DOI: https://doi.org/10.1007/BF01151297