Chlorotrimethylsilane → N-(2-(2-(4-Hydroxy-4-(pyridin-3-yl)piperidin-1-yl)-2-oxoethoxy)ethyl)-4-methoxy-N,2,6-trimethylphenylsulfonamide hydrochloride

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Reaction Steps

N,N′-Carbonyldiimidazole (77 mg, 0.475 mmol) was added to a solution of 2-(2-(4-methoxy-N,2,6-trimethylphenylsulfonamido)ethoxy)acetic acid (acid unit S2) (150 mg, 0.453 mmol) in methylene chloride (5 ml) and the mixture was stirred for 1 h at room temperature. A solution of 4-(pyridin-3-yl)piperidin-4-ol (A2) (80 mg, 0.453 mmol) in methylene chloride (2 ml) was subsequently added and the reaction mixture was stirred for 15 h at room temperature. Thereafter, saturated sodium bicarbonate solution (10 ml) was added to the reaction mixture and the aqueous phase was subsequently extracted with methylene chloride (20 ml). The combined organic phases were extracted with saturated sodium chloride solution (10 ml), dried with sodium sulfate and concentrated in vacuo. The crude product was purified by flash chromatography with diethyl ether/methylene chloride/methanol/ammonia solution (25% aq.) (50:50:5:1). N-(2-(2-(4-Hydroxy-4-(pyridin-3-yl)piperidin-1-yl)-2-oxoethoxy)ethyl)-4-methoxy-N,2,6-trimethylphenylsulfonamide (170 mg. 0.346 mmol) was dissolved in diethyl ether/methyl ethyl ketone (15:1, 32 ml), and chlorotrimethylsilane (81 μl, 0.692 mmol) was slowly added. The mixture was subsequently stirred for 30 min at 0° C. The precipitate formed was filtered off, washed with diethyl ether/hexane and dried.

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