Methyl 2-amino-3-nitrobenzoate → 2,3-Diaminobenzoic acid methyl ester

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Reaction Steps

To a nitrogen-saturated solution of 2-amino-3-nitrobenzoic acid methyl ester (Chess GmbH, 50 g, 0.26 mol) in absolute ethanol (800 mL) was added palladium hydroxide (Degussa, 20% w/w on carbon, 58.75% w/w water, 10 g). The slurry was degassed then shaken vigorously under hydrogen (4 atm) at room temperature for 48 h. The catalyst was filtered and the filtrate concentrated in vacuo to afford 2,3-diaminobenzoic acid methyl ester as a dark orange oil that solidified on standing (43 g, 0.26 mol, 100%). (m/z): [M-OCH3]+ calcd for C8H10N2O2 135.05. found 135.3. 1H NMR (300 MHz, DMSO-d6): δ (ppm) 3.74 (s, 3H), 4.80 (br s, 1H), 6.20 (br s, 1H), 6.38 (t, 1H), 6.70 (d, 1H), 7.06 (d, 1H).

Provenance & Evidence