Dehydrocyanation of 2,5-diaryl-3,3,4,4-tetracyanopyrrolidines

A second direction has been found in the thermal conversions of 2,5-diaryl-3,3,4,4-tetracyanopyrrolidines. When they are refluxed in DMF or DMSO in the presence of a base, rearrangement does not take place, but rather elimination of two molecules of hydrogen cyanide and the formation of 2,5-diaryl-3,4-dicyanopyrroles. It was shown that 2,6-diphenyl-4,5-dicyanopyrrolo[2,3-d]pyrimidine is formed when the basicity of the medium is within certain limits.