Bromination of 4-aryl-3,5-dialkoxycarbonyl-2,6-dimethyl-1,4-dihydropyridines

4-Aryl-3,5-dialkoxycarbonyl-2,6-dimethyl-1,4-dihydropyridines are brominated by N-bromosuccinimide in methanol at room temperature at the methyl groups at positions 2 and 6 to form mono-, di-, tri-, and tetrabromo derivatives. When the N-unsubstituted bromomethyl-1,4-dihydropyridines are heated they are easily converted to tetrahydrofuropyridines, but in the case of the analogous N-substituted-1,4-dihydropyridines cyclization does not occur. The 2,6-bis(bromomethyl)-substituted products easily replace bromine under the influence of nucleophilic reagents.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1230–1235, September, 1991.