2-Ethylpyridine → HCID 18956529, compound

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Reaction Steps

n-Butyllithium (19.7 ml of a 1.6M solution in hexane) was added to a stirred solution of diisopropylamine (3.18 g) in dry tetrahydrofuran (50 ml) at -70° under an atmosphere of dry nitrogen. The solution was stirred at -70° for 0.17 hour, followed by 0.17 hour at 0° and then re-cooled to -70°. 2-Ethylpyridine (3.37 g) was added over 0.08 hour, the red solution resulting was stirred at -70° for 0.33 hour and then added via a syringe to a stirred solution of 2-chloro-2',4'-difluoroacetophenone (5.00 g) in dry tetrahydrofuran (50 ml) at -70°. The solution was stirred at -70° for 3 hours and then at room temperature for 18 hours. Water (4 ml) was added and the solution was evaporated. The residual oil was partitioned between water (80 ml) and dichloromethane (100 ml). The organic layer was separated, washed with water (80 ml) and then extracted with 2N hydrochloric acid (2×80 ml). The combined acidic extracts were basified to pH 12 with 2N sodium hydroxide solution and extracted with dichloromethane (3×75 ml). The combined organic layers were dried (Na2SO4), evaporated, and the residue was chromatographed on silica gel. Elution with ethyl acetate gave, after combination and evaporation of appropriate fractions, the title compound (2.25 g) as a yellow oil which was used directly in the next stage.

Provenance & Evidence