2H-3,1-Benzoxazine-2,4(1H)-dione, 6-nitro- → 2-Amino-5-nitrobenzyl alcohol

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Reaction Conditions

Reaction Steps

5-Nitroisatoic anhydride (4.0 g, 19.22 mmol) is suspended in ethanol (32 mL) and cooled to 0° C. using an ice bath under a nitrogen atmosphere. A solution of 2.18 g (57.66 mmol) of sodium borohydride in 16 mL of 0.1 M NaOH is added dropwise over 25 minutes while keeping the temperature at 0-18° C. using an ice bath. The reaction mixture is stirred at room temperature for 3 hours, cooled in an ice bath, and carefully quenched by the addition of 6N sulfuric acid (6.5 mL) over a period of 20 minutes (0-37° C.), followed by stirring for an additional 20 minutes at 0° C. After neutralization with 6N NaOH (10 mL), the reaction mixture is poured onto 30 mL of ice water and 10 mL of 0.1 M NaOH. The orange-yellow solid is isolated by vacuum filtration and washed with water (70 mL). The resulting solid is stirred in 0.1 N NaOH (30 mL) for 95 minutes, isolated by vacuum filtration, and washed with water (3×25 mL). The yellow solid is dried under vacuum at 60° C. to constant weight, affording 2.75 g (80%) of product; 1H-NMR (300 MHz, DMSO-d6); δ 8.05 (s, 1H), 7.90 (d, J=8.6 Hz, 1H), 6.65 (d, J=8.9 Hz, 1H), 6.45 (s, 2H), 5.32 (br s, 1H), 4.39 (d, J=4.65 Hz, 2H).

Provenance & Evidence