反应详情

To a solution of 2-methyl-isonicotinic acid ethyl ester (3.20 g) and tert-butyl acetate in n-heptane at −5° C. was slowly added lithium hexamethyldisilazide (46.5 mL; 1 M solution in THF). After stirring for 2 h, a solution of sulfuric acid (4.13 mL) in water (20 mL) was added within 20 min keeping the reaction temperature below 10° C. After the addition was completed, the reaction mixture was heated to reflux overnight. Extraction over a sat. solution of NaHCO3 (100 mL) with ethyl acetate (3×50 mL) and drying of the combined organic phases over Na2SO4 provided after evaporation of the organic solvent the title compound as a light brown liquid (2.40 g, 92%), which was used for the consecutive step without any further purification, MS (ESI+): m/z=136.0 [M+H]+.

1. customat −5° C.
2. customthe reaction temperature below 10° C
3. additionAfter the addition
4. temperaturethe reaction mixture was heated
5. temperatureto reflux overnight
6. extractionExtraction over a sat. solution of NaHCO3 (100 mL) with ethyl acetate (3×50 mL)
7. dry with materialdrying of the combined organic phases over Na2SO4
8. customprovided
9. customafter evaporation of the organic solvent the title compound as a light brown liquid (2.40 g, 92%), which
10. customwas used for the consecutive step without any further purification, MS (ESI+)