Sodium methanethiolate → 2-Chloro-3-fluoro-5-methylthiomethylpyridine

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Reaction Steps

A solution of 2-chloro-3-fluoro-5-bromomethylpyridine (3.7 g, 16.5 mmol) in ethanol (40 mL) was treated with sodium thiomethoxide solid (2.31 g, 33 mmol) portionwise at 0° C. After the addition was over, the mixture was stirred at room temperature overnight. Most of the solvent ethanol was removed under reduced pressure and the residue was re-taken into dichloromethane. Brine solution was added and two phases mixed and separated. The organic layer was dried over anhydrous Na2SO4, filtered and concentrated. The resulting residue was purified on silica gel using 8% EtOAc in hexane as eluent to give 2.04 g of the desired 2-chloro-3-fluoro-5-methylthiomethylpyridine in 65% yield. GC-MS calcd. for C7H7ClFNS: 191.66. Found: 191.

Provenance & Evidence