Catalytic hydrogenation of 2,5-bis(p-nitrophenyl)pyrimidine

We have studied the catalytic hydrogenation of 2,5-bis(p-nitrophenyl)pyrimidine over palladium on carbon under different conditions. We have established that hydrogenation in acetic acid at atmospheric hydrogen pressure leads to formation of 2,5-bis(p-aminophenyl)-1,4,5,6-tetrahydropyrimidine. Upon hydrogenation under pressure in DMF, along with 2,5-bis(p-aminophenyl)pyrimidiine, three isomeric (aminophenyl)pyrimidyl-substituted benzenes are formed as by-products. The mixture of these arylazo derivatives can be smoothly reduced by hydrogen under pressure in the presence of Raney nickel to bis(aminophenyl)pyrimidine.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1534–1539, November, 1993.We would like to acknowledge V.I. Mamatyuk and M. M. Shakirov for helping record and interpret the PMR spectra.