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 stannous (II) chloride dihydrate (24.2 g, 107 mmol) was added. The suspension was stirred on an oil-bath at 75° C for 2 hours and concentrated in vacuo. Ethyl acetate (100 mL) and water (50 mL) was added and pH was adjusted to pH 8 with 4 N sodium hydroxide (50 mL). The liquid was decanted from the precipitation. The precipitate was washed twice with ethyl acetate. The aqueous phase was extracted twice with ethyl acetate (60 mL). The combined organic phases were washed with a saturated sodium chloride solution (2×100 mL), dried (magnesium sulphate) and concentrated in vacuo. Purification by column chromatography (120 g silica) using ethyl acetate and heptane (1:1) as eluent afforded 3.8 g of 5-amino-2-trifluoromethoxybenzoic acid methyl ester.

1. concentrationconcentrated in vacuo
2. additionEthyl acetate (100 mL) and water (50 mL) was added
3. customThe liquid was decanted from the precipitation
4. washThe precipitate was washed twice with ethyl acetate
5. extractionThe aqueous phase was extracted twice with ethyl acetate (60 mL)
6. washThe combined organic phases were washed with a saturated sodium chloride solution (2×100 mL)
7. dry with materialdried (magnesium sulphate)
8. concentrationconcentrated in vacuo
9. customPurification by column chromatography (120 g silica)

ORD record

ord-f1e8da5c88fa4c26b3fb4e430069115f

Source dataset

uspto-grants-2003_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06562807B2