Hydrochloric Acid → 2,2-Dimethyl-7-(2-dimethylaminoethoxy)-4-phenyl-2H-chromene

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Reaction Steps

To a stirred solution of phenylmagnesium bromide [from bromobenzene and magnesium in dry tetrahydrofuran] was added 2,2-dimethyl-7-(2-dimethylaminoethoxy)-chroman-4-one in dry THF and the resulting solution was boiled under reflux for 2 weeks. The cooled reaction mixture was decomposed with 2.5 N hydrochloric acid and the organic layer separated and dried (magnesium sulphate). Removal of the solvent gave a yellow oil which was chromatographed on silica in 3% ether -- 97% light petroleum (b.p. 60°-80°) gave the title compound as a colourless oil. Dissolution in dry ether and passage of dry hydrogen chloride through the solution gave the hydrochloride salt, m.p. 186.5°-187.5°. An analogous procedure yielded 7-(2-N-benzyl-N-methyl-aminoethoxy)-4-(4-fluorophenyl)-2,2-dimethyl-2H-chromene as a colourless oil.

Provenance & Evidence