反应详情

Thionyl chloride (2.88 mL, 39.69 mmol) was added drop wise to a solution of 2-amino-5-methyl-benzoic acid (3.0 g, 19.84 mmol) in methanol (10 mL) at 0° C. and refluxed for 16 hr. The reaction mixture was concentrated to dryness and the residue dissolved in chloroform (100 mL). The organic layer was washed with sodium bicarbonate solution (5×30 mL), water (3×30 mL), brine (3×30 mL) and dried over anhydrous sodium sulphate. The residue was concentrated under vacuum to yield the crude compound, which was purified by column chromatography over silica gel (100-200 mesh) using 2% ethyl acetate in pet ether as eluent to afford 2-amino-5-methyl-benzoic acid methyl ester (2.0 g, 61%) as a pale yellow semi solid.

1. temperaturerefluxed for 16 hr
2. concentrationThe reaction mixture was concentrated to dryness
3. dissolutionthe residue dissolved in chloroform (100 mL)
4. washThe organic layer was washed with sodium bicarbonate solution (5×30 mL), water (3×30 mL), brine (3×30 mL)
5. dry with materialdried over anhydrous sodium sulphate
6. concentrationThe residue was concentrated under vacuum
7. customto yield the crude compound, which
8. customwas purified by column chromatography over silica gel (100-200 mesh)