Isopropanol → 3-Amino-5,6,7,8-tetrahydronaphthalene-2-carboxylic acid

Temperature

90 °C

To a mixture of activated Raney Nickel (200 g of 50% slurry in water on aluminum; 700 mmol, 13 equiv) and 3-amino-2-naphthoic acid (1-1) (10 g, 53 mmol, 1 equiv) in 1:1 isopropanol:water (400 mL) at 90° C. was added 1% aqueous NaOH solution (200 mL) over 1 h. The reaction mixture was stirred for 16 h at 90° C. and additional Raney Nickel (50 g, 180 mmol, 3.4 equiv) was added and the resulting mixture was heated at 90° C. for 24 h. The mixture was filtered and the filtrate was concentrated to 200 mL of water and brought to pH=3 with the addition of 1N aqueous hydrochloric acid solution to precipitate the product. The off-white precipitate was filtered, and purified by reverse phase liquid chromatography (H2O/CH3CN gradient w/0.1% TFA present) to yield 3-amino-5,6,7,8-tetrahydronaphthalene-2-carboxylic acid (1-2) as a white solid. LRMS m/z (M+H) 192.2 found, 192.1 required.

1. temperaturethe resulting mixture was heated at 90° C. for 24 h
2. filtrationThe mixture was filtered
3. concentrationthe filtrate was concentrated to 200 mL of water
4. additionbrought to pH=3 with the addition of 1N aqueous hydrochloric acid solution
5. customto precipitate the product
6. filtrationThe off-white precipitate was filtered
7. custompurified by reverse phase liquid chromatography (H2O/CH3CN gradient w/0.1% TFA present)

ORD record

ord-029665ea0da8455484d534836bd60ae9

Source dataset

uspto-grants-2009_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07550477B2