6-Nitrophthalide → 6-Aminophthalide

Commercially available 6-nitro-1(3H)-isobenzofuranone (9.9 g, 55 mmol) was dissolved in a mixed solvent of tetrahydrofuran (20 ml)-methanol (60 ml), then 5% palladium-charcoal catalyst (1.5 g) was added thereto, and the mixture was stirred at room temperature for 20 hours under an atmosphere of hydrogen gas. The reaction mixture was filtered, and the solid was washed successively with ethyl acetate and methanol. The filtrate and washings were combined, and the resulting solution was concentrated under reduced pressure. The obtained solid was washed with ethyl acetate to give the title compound (6.21 g) as a crystalline solid. The washings were concentrated, and the residue was crystallized from a mixed solvent of ethyl acetate-hexane to give an additional amount of the title compound (0.95 g, total yield 87%).

1. filtrationThe reaction mixture was filtered
2. washthe solid was washed successively with ethyl acetate and methanol
3. concentrationthe resulting solution was concentrated under reduced pressure
4. washThe obtained solid was washed with ethyl acetate

ORD record

ord-de3c21be4ca04b5da0c209197eb7da69

Source dataset

uspto-grants-2007_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07230023B2