Synthesis of 2,2′-bipyrimidine derivatives

A new total synthesis of 2,2′ -bipyrimidine derivatives by the direct condensation of 2-amidinopyrimidinebenzenesulfonate with dicarbonyl compounds is described. The following 2,2′-bipyrimidines have been prepared: 5-ethyl-4,6-dihydroxy-2,2′-bipyrimidine; 5-ethyl-4,6-dichloro-2,2 -bipyrimidine; 4,6-dihydroxy-2,2′ -bipyrimidine; 5-ethyl-4,6-dimethoxy-2,2′ -bipyrimidine.