FLUORO-ORGANICS - TRIFLUOROMETHYL GROUP-INDUCED O-ALKYLATION OF PYRIDIN-2-ONES

The effect of a trifluoromethyl group on the alkylation of pyridin-2-o nes, using alpha-haloesters, alpha-haloamides, allyl halides and chlor oacetonitrile, has been studied. In all cases, the corresponding 2-O-a lkylated products were obtained exclusively, irrespective of the natur e of alkylating agent. The study indicates that the trifluoromethyl gr oup present at the 4 or 6 position of the pyridin-2-one ring enhances the charge density on the 2-oxo group leading to the exclusive formati on of O-alkylated products. If the electronic effect induced by the 4- trifluoromethyl group is mitigated by a 6-methyl substituent, the resu lt is a mixture of N- and O-alkylated products, in conformity with the proposed rationalisation.