Phosphorus pentachloride → N-(2-chloro-4-trifluoromethoxyphenyl)-5-(methylsulfonyl)picolinimidoyl chloride

Participants

Reaction Steps

5-Methanesulfonyl-pyridine-2-carboxylic acid (2-chloro-4-trifluoromethoxy-phenyl)-amide 7 (1.1 g, 2.79 mmol) in benzene (20 mL) was added to PCl5 (1.26 g, 6.0 mmol) and the mixture was heated to reflux overnight. The solvent was removed and the residue was further dried under high vacuum. Crude N-(2-chloro-4-trifluoromethoxyphenyl)-5-(methylsulfonyl)picolinimidoyl chloride was obtained as a yellow solid (1.60 g). The N-(2-chlor-4-trifluoromethoxyophenyl)-5-(methylsulfonyl)picolinimidoyl chloride was dissolved into anhydrous THF (30 mL) and the reaction was cooled down to 0° C. and hydrazine monohydrate (9.0 mL) was added. The reaction was kept at 0° C. for 10 min and warmed to ambient temperature in 0.5 h. The solvent was removed and the residue was purified by column chromatography (eluting with hexane and ethyl acetate 1:1) to give N′-(2-chloro-4-trifluoromethoxyphenyl)-5-(methylsulfonyl)picolinimidohydrazide 8 as a yellow solid. Yield: 0.56 g, 50%.

Provenance & Evidence