Methyl iodide → Methyl 2-amino-3-nitrobenzoate

2-Amino-3-nitrobenzoic acid may be prepared as described in Chapman, E. and Stephen, H., "Preparation of phthalmic acids and their conversion to anthranilic acids," J. Chem. Soc., (1925), 1151. To a mixture of this acid (14.00 g, 76.9 mmol) and cesium carbonate (20.00 g, 61.5 mmol) in dimethylformamide (150 mL) at 0° C. methyl iodide (12.00 g, 84.5 mmol) was added with stirring. After 20 minutes, it was warmed to room temperature and stirred for 3 hours. Most of the solvent was removed in vacuo and the residue was partitioned between ethyl acetate (250 mL) and water (100 mL). The organic layer was separated, the aqueous layer was washed with ethyl acetate (250 mL) and the combined organic extract was dried over magnesium sulfate. After concentrating, the residue was triturated with ether to obtain the first crop of product as a yellow solid (3.20 g). The filtrate solution was concentrated, and the residue was passed through a flash column on silica gel eluting with 4:1 hexane:ethyl acetate to afford a slightly impure product. This material was triturated with methanol to obtain a pure second crop of product (9.10 g); total 12.3 g in 82% yield.

1. additionwas added
2. stirringstirred for 3 hours
3. customMost of the solvent was removed in vacuo
4. customthe residue was partitioned between ethyl acetate (250 mL) and water (100 mL)
5. customThe organic layer was separated
6. washthe aqueous layer was washed with ethyl acetate (250 mL)
7. extractionthe combined organic extract
8. dry with materialwas dried over magnesium sulfate
9. concentrationAfter concentrating
10. customthe residue was triturated with ether

ORD record

ord-c61fbb8c2fa64cabb44682ea64b3ffcf

Source dataset

uspto-grants-1995_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05380719