1-Acetoxy-2-bromoethane → 2-{4-(1,3-benzodioxol-5-yl)-5-methoxy-3-[(methoxymethyl)(phenethylsulfonyl)amino]-1H-pyrazol-1-yl}ethyl Acetate

Participants

Reaction Steps

Sodium hydride (60% dispersion in oil, 162 mg) was added at room temperature under an atmosphere of nitrogen to a solution of N-[4-(1,3-benzodioxol-5-yl)-3-methoxy-1H-pyrazol-5-yl]-N-(methoxymethyl)-2-phenyl-1-ethanesulfonamide (Preparation 55) in anhydrous tetrahydrofurane. After 10 minutes, 2-bromoethyl acetate (446 μl) was added and the reaction mixture was refluxed overnight. At room temperature, some more 2-bromoethylacetate (446 μl) was added and the reaction was refluxed for 24 h. Then at room temperature, some more sodium hydride (50 mg) was added and the reaction was refluxed for 24 h. At room temperature, the reaction was quenched by the addition of an aqueous saturated solution of ammonium chloride (5 ml), water (10 ml) and the mixture was extracted with ethyl acetate (3×10 ml). The combined organic fractions were washed with brine (20 ml), dried on sodium sulfate and concentrated under reduced pressure to yield a dark oil which was purified by column chromatography (silica, 10 g), eluted with hexane:ethyl acetate (4:1) then (2:1) yielding the title compound as a colourless oil (92 mg).

Provenance & Evidence