(Dimethyl sulfide)trihydroboron → (+,-) Trans Propane-2-sulfonic Acid {2-[4'-(2-amino-ethyl)-biphenyl-4-yl]-cyclopentyl}-amide

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Reaction Steps

(+,−) Trans propane-2-sulfonic acid [2-(4′-cyanomethyl-biphenyl-4-yl)-cyclopentyl]-amide (210 mg, 0.55 mmol, prepared in example 8) was dissolved in 20 mL dry THF. To this solution was added 0.83 mL (1.65 mmol) of a 2.0 M solution of borane dimethyl sulfide in THF. The reaction was heated to reflux for 4 hours then concentrated in vacuo. To this solid was added 30 mL of diethyl ether, 15 mL of concentrated HCl, 10 mL of water, and 5 mL of methanol and stirred at room temperature for 30 minutes. The aqueous layer was separated, and the organic phase washed 1× with water. The combined aqueous phases were made basic with sodium hydroxide at 0° C. and extracted into diethyl ether (2×50 mL) followed by ethyl acetate (1×50 mL). The combined organic phases were dried over sodium sulfate, filtered, and concentrated to a crude oil which was used without further purification.

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