HSAB driven chemoselectivity in alkylation of uracil derivatives. A high yielding preparation of 3-alkylated and unsymmetrically 1,3-dialkylated uracils

Article abstract of DOI:10.1016/S0040-4020(99)00736-X

A qualitative hardness scale (N¹34) has been found for the conjugated bases of 2-methoxy-4(3H)-pyrimidinones 1-3 and applied to high yielding chemoselective N³ methylation, ethylation and benzylation reactions. Removal of the 2-methoxy group followed by a second alkylation affords unsymmetrically 1,3-disubstituted uracils.