Reaction of pyrimidin-2(1H)-ones and -thiones with organometallic compounds. Regioselective preparation of dihydropyrimidin-2(1H)-ones and -thiones

Abstract

4,6-Dimethyl-1-phenylpyrimidin-2(1H)-one (1) reacted with methylmagnesium iodide to afford 4,6,6-trimethyl-1-phenyl-3,6-dihydropyrimidin-2(1H)-one (8a) selectively; compound (1) reacted with methyl-lithium to give mainly 4,4,6-trimethyl-1-phenyl-3,4-dihydropyrimidin-2(1H)-one (8b). The reactions of various pyrimidin-2(1H)-ones and -thiones with organometallic compounds, and the influence of bulkiness of alkyl groups upon the product ratio, are also discussed.