2-Dimethylaminopyridine → (E)-N-[4-(1,3-benzodioxol-5-yl)-1-benzyl-3-methoxy-1H-pyrazol-5-yl]-2-phenyl-1-ethenesulfonamide

Beteiligte Stoffe

Reaktionsschritte

(E)-2-phenylethensulfonyl chloride (138 mg) and dimethylaminopyridine (40 mg) were added at room temperature under an atmosphere of nitrogen to a solution of 4-(1,3-benzodioxol-5-yl)-1-benzyl-3-methoxy-1H-pyrazol-5-amine (Preparation 58) (100 mg) in anhydrous pyridine (3 ml). After 24 h, another portion of (E)-2-phenylethensulfonyl chloride (32 mg) was added and the reaction was stirred for 48 h before the mixture was concentrated under reduced pressure. To the beige solid was added an aqueous solution of HCl (1N, 10 ml) and the mixture was extracted with dichloromethane (3×10 ml). The organic fractions were combined, dried on sodium sulfate and concentrated under reduced pressure. The residue was dissolved in ethanol (5 ml) and an aqueous solution of sodium hydroxyde (2N, 2.25 ml) was added. The reaction was stirred overnight. The reaction mixture was then diluted with water (20 ml), acidified with an aqueous solution of HCl (2N) and the solution was extracted with ethyl acetate (3×15 ml). The combined organic fractions were washed with brine (15 ml), dried on sodium sulfate and concentrated under reduced pressure. The residue was purified by column chromatography (silica, 10 g) eluted with hexane:ethyl acetate (2:1) to yield the title compound as colourless oil (109 mg) which crystallises in a mixture of ether and ethyl acetate.

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