Sodium Carbonate → 6-Chloro-3-methyl-5-(3-trifluoromethyl-phenyl)-pyridine-2-carboxylic acid methyl ester

참여 물질

반응 조건

반응 단계

3.48 g (11.2 mmol) of 3-methyl-1-oxy-5-(3-trifluoromethyl-phenyl)-pyridine-2-carboxylic acid methyl ester [prepared from 3-methyl-5-(3-trifluoromethyl-phenyl)-pyridine-2-carboxylic acid methyl ester (intermediate 1A) by reaction with 3-chloro-perbenzoic acid in analogy to the procedure described for the preparation of intermediate 1C] was added at RT while stirring to 20.4 ml=34.25 g (223.3 mmol) of phosphorus oxychloride and the reaction mixture was warmed up to 50° C. After 2 hours, it was cooled down to RT and poured into crashed ice. This solution was carefully neutralized with solid sodium carbonate and extracted twice with EtOAc; the organic phases were washed with water, dried over magnesium sulfate, filtered and evaporated. The residue was purified by flash column chromatography (heptane/CH2Cl2 1:1 to 0:1) to give 2.52 g (68%) 6-chloro-3-methyl-5-(3-trifluoromethyl-phenyl)-pyridine-2-carboxylic acid methyl ester as light yellow oil; [MS: 330.0 (MH+, 1Cl)] and 1.10 g (30%) 4-chloro-3-methyl-5-(3-trifluoromethyl-phenyl)-pyridine-2-carboxylic acid methyl ester as colorless solid. MS: 330.0 (MH+, 1Cl).

출처 및 근거