Hilbert-Johnson reactions of 2,2',4',6-Tetramethoxy-4,5'-bipyrimidine

Abstract

2,2',4',6-Tetramethoxy-4,5'-bipyrimidine (1) was converted successively by methyl iodine into 2,4',6-trimethoxy-l'-methyl-4,5'-bipyrimidin-2'-one (2a), a single dimethoxy-1,1'-dimethyl-4,5'-bipyrimidinedione (3 or 4; not positively identified), 4'-methoxy-1,1',3-trimethyl-4,5'-bipyrimidine- 2,2',6-trione (5) and 1,1',3,3'-tetramethyl-4,5'-bipyrimidine-2,2,4',6-tetrone (6e). Hydrolysis of the first three products gave respectively, the 1'-methyl, 1,1'-dimethyl and 1,1',3-trimethyl derivatives (6b-d) of 4,5'-bipyrimidine-2,2',4',6-tetrone. Structures were elucidated by n.m.r., ultraviolet and mass spectra.