反应详情

温度

50 °C

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).

1. additionwas added at RT
2. temperatureit was cooled down to RT
3. additionpoured
4. extractionextracted twice with EtOAc
5. washthe organic phases were washed with water
6. dry with materialdried over magnesium sulfate
7. filtrationfiltered
8. customevaporated
9. customThe residue was purified by flash column chromatography (heptane/CH2Cl2 1:1 to 0:1)