S-2-Pyridinyl 4-bromo-2-chlorobenzenecarbothioate → 1-(4-Bromo-2-chlorophenyl)ethan-1-one

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Reaction Conditions

Reaction Steps

4-Bromo-2-chloro-thiobenzoic acid S-pyridin-2-yl ester (1.86 g, 5.66 mmol) from Step 1 above was dissolved in dry THF (30 mL) and cooled to −78° C. A solution of methyl magnesium bromide in 75:25 toluene/THF (1.4 M, 4.45 mL, 6.23 mmol) was added dropwise. After stirring 35 min, the cooling bath was removed. The reaction mixture was quenched with saturated 1N HCl and extracted with EtOAc (30 mL). The organic phase was washed with brine (50 mL), dried over Na2SO4 and evaporated. The residue was purified by flash column chromatography (10% EtOAc in hexanes) to give the product (1.05 g, 80%) as a colorless oil. 1H NMR (CDCl3) δ 2.64 (s, 3H), 7.46-7.48 (m, 2H), 7.61 (s, 1H).

Provenance & Evidence