Investigation of the reaction of 1-methyl-2,5-dichloro-3,4-diformylpyrrole with amines

The reaction of 1-methyl-2,5-dichloro-3,4-diformylpyrrole with amines of the aliphatic series leads to products of replacement of one chlorine atom. With aromatic amines the reaction takes place at one of the formyl groups to give aminals. The latter in the presence of excess amine readily give bisazomethines of 1-methyl-2-chloro-5-arylamino-3, 4-diformylpyrrole, which can also be obtained directly by the reaction of dichlorodiformylpyrrole with arylamines. It is shown that in this case one of the formyl groups and the adjacent chlorine atom react initially, after which the second formyl group reacts. The chlorine atom in bisazomethines of 1-methyl-2-chloro-5-arylamino-3,4-diformylpyrrole has high nucleophilic lability and is easily replaced by a hydroxy group or a piperidine residue.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1489–1493, November, 1981.