4-[(2-Methylbut-3-yn-2-yl)oxy]benzonitrile → 4-[1,1-Dimethyl-3-(2-quinolyl)-2-propynyloxy]benzonitrile

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Reaction Steps

The 2,2-dimethyl-4-(2-quinolyl)-2H-1-benzopyran-6-carbonitrile used as the starting material was prepared as follows: (A) 5.1 g of 2-iodoquinoline were added at room temperature to a solution of 18 mg of palladium(II) chloride, 52 mg of triphenylphosphine and 38 mg of copper(I) iodide in 100 ml of diethylamine. 3.7 g of 4-(1,1-dimethyl-2-propynyloxy)benzonitrile were added. After stirring at room temperature for 18 hours the mixture was evaporated and the residue was dissolved in ethyl acetate and water. The organic phase was dried over sodium sulphate and evaporated. The residue was chromatographed on silica gel using ethyl acetate/petroleum ether (1:2) for the elution to give 5.8 g of 4-[1,1-dimethyl-3-(2-quinolyl)-2-propynyloxy]benzonitrile as a yellow gum. (B) 5.8 g of 4-[1,1-dimethyl-3-(2-quinolyl)-2-propynyloxy]benzonitrile were heated at reflux for 2 hours in 50 ml of dichlorobenzene. The mixture was allowed to cool to room temperature and was then evaporated to dryness. The residue was chromatographed on silica gel using ethyl acetate/petroleum ether (1:3) for the elution. The product was recrystallized from isopropanol to give 2.1 g of 2,2-dimethyl-4-(2-quinolyl)-2H-1-benzopyran-6-carbonitrile of melting point 102°-104° C.

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