Methyl 5-nitro-2-(trifluoromethoxy)benzoate → Methyl 5-amino-2-(trifluoromethoxy)benzoate

Temperature

75 °C

5-Nitro-2-trifluoromethoxybenzoic acid methyl ester (5.69 g, 21.5 mmol) was dissolved in ethanol 99.9% (80 mL) and added stannous(II)chloride dihydrate (24.2 g, 107 mmol). The suspension was stirred at 75° C. for 2 hours and then concentrated in vacuo. The residue was added ethyl acetate (100 mL) and water (50 mL) and pH was adjusted to pH 8 with 4 N sodium hydroxide (50 mL). The liquid was decanted from the fine precipitation, which occurred, and the precipitate was washed with ethyl acetate and decanted twice. The combine organic phases were washed with water:saturated sodium chloride (1:1) solution (2×100 mL), dried (magnesium sulphate) and concentrated in vacuo. The residue was purified by column chromatography (120 g silica) using ethyl acetate:heptane (1:1) as eluent to give 3.8 g of 5-amino-2-trifluoromethoxybenzoic acid methyl ester.

1. concentrationconcentrated in vacuo
2. additionThe residue was added ethyl acetate (100 mL) and water (50 mL) and pH
3. customThe liquid was decanted from the fine precipitation, which
4. washthe precipitate was washed with ethyl acetate
5. customdecanted twice
6. washThe combine organic phases were washed with water
7. dry with materialsaturated sodium chloride (1:1) solution (2×100 mL), dried (magnesium sulphate)
8. concentrationconcentrated in vacuo
9. customThe residue was purified by column chromatography (120 g silica)

ORD record

ord-ea44f1d787784dcfaca6ab53535f1696

Source dataset

uspto-grants-2003_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06562807B2