Highly regioselective bromination reactions of polymethylpyrimidines
摘要:
4,5-Dimethyl- and 4,5,6-trimethyl-substituted pyrimidines are brominated at C5-Me with NBS in CCl4 and at C4(6)-Me with bromine in acetic acid to give the corresponding bromomethyl derivatives in a high yield. The remaining methyl group(s) can also be brominated with high regioselectivity. The 2-methylthio substituent is not oxidized under these conditions.