Ethyl Acetate → 2,3-Diaminobenzoic acid methyl ester

2-Amino-3-nitro-benzoic acid methyl ester (50.7 g, 258.7 mmol) was suspended in methanol (441 ml) and ethyl acetate (441 ml) with palladium-on-active charcoal 10% (1.93 g, 1.81 mmol). The suspension was hydrogenated at room temperature under an H2 pressure of 2.5 bar. When the reaction was complete, the suspension was filtered over Celite and the residue was rinsed with ethyl acetate. The filtrate was concentrated to dryness under reduced pressure, the residue was dissolved in ethyl acetate (50 ml) and hexane (50 ml) was added. After addition of starting crystals, a precipitate precipitated out. Hexane (200 ml) was added to the suspension and the precipitate was filtered off, washed with hexane and dried in vacuo. Methyl 2,3-diaminobenzoate (D-01) was obtained (35.8 g, 83%).

1. customwas hydrogenated at room temperature under an H2
2. filtrationthe suspension was filtered over Celite
3. washthe residue was rinsed with ethyl acetate
4. concentrationThe filtrate was concentrated to dryness under reduced pressure
5. dissolutionthe residue was dissolved in ethyl acetate (50 ml)
6. additionhexane (50 ml) was added
7. additionAfter addition
8. customa precipitate precipitated out
9. additionHexane (200 ml) was added to the suspension
10. filtrationthe precipitate was filtered off
11. washwashed with hexane
12. customdried in vacuo

ORD record

ord-557db6142f3c44989e618b872424f39f

Source dataset

uspto-grants-2012_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08232288B2