3-Quinolin-3-ylprop-2-yn-1-ol → 3-(Quinolin-3-yl)prop-2-en-1-ol

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Reaction Steps

To a dry, jacketed 250-mL three-necked round-bottom flask was charged sodium bis(2-methoxyethoxy)aluminum hydride (Red-Al, 70% wt. solution in toluene, 11.0 g, 38.1 mmol, 1.39 eq) and anhydrous THF (20 mL). To this precooled (0-2° C.) and magnetically stirred solution was added a THF (50 mL) solution of the 3-(3-quinolyl)-2-propyn-1-ol (5.0 g, 27.32 mmol) via pressure equalizing dropping funnel. The temperature was not allowed to rise above 15° C. After the addition was complete (20 minutes) the mixture was allowed to warm up to room temperature and stirred for one hour. The solution was then cooled to 0° C. and quenched by the addition of aqueous 10% sulfuric acid (20 mL) such that the internal temperature did not rise above 15° C. The biphasic reaction mixture was then washed with ethyl acetate (3×100 mL). The pH of the aqueous acidic product solution was then adjusted to pH 9-10 with aq. conc. NH4OH and back extracted into ethyl acetate (2×125 mL). The combined organic layers were dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure to give exclusively 3-(3-quinolyl) trans-2-propen-1-ol as a solid: 4.1 g, 81%.

Provenance & Evidence