Lithium Hexamethyldisilazide → 1-[(5-Chloro-3-methyl-1-benzothien-2-yl)sulfonyl]-4-[3-(trifluoromethyl)pyridin-2-yl]piperazin-2-one

Participants

Reaction Conditions

Reaction Steps

A solution of 4-(3-(trifluoromethyl)pyridin-2-yl)piperazin-2-one (150 mg, 0.61 mmol) in anhydrous THF (2.0 mL) was cooled to −78° C., followed by drop-wise addition of LHMDS (0.92 mL, 0.92 mmol (1.0 Min THF)). The reaction was allowed to stir five minutes after which a solution of 5-chloro-3-methyl-2-benzothiophene sulfonyl chloride in anhydrous THF (221 mg, 0.79 mmol in 1 mL) was added drop-wise. The reaction mixture was allowed to stir at −78° C. for approximately two hours, after which it was judged complete by TLC. The reaction was quenched with excess H2O (10 mL), extracted into ethyl acetate (3×10 mL), and finally washed with aqueous NaHCO3 (2×10 mL). The organic layers were combined and dried over Na2SO4, decanted, and concentrated in vacuo. The resultant crude oil was purified via normal phase SiO2 column chromatography using a 5%-20% EA/Hex solvent gradient. The desired product, was isolated in >95% purity, 3.5% yield (10 mg).

Provenance & Evidence