Sulfamic Acid → 4-Methoxy-3-(4-methoxy-butyl)-benzoic acid

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Reaction Steps

To a stirred suspension of 4-methoxy-3-(4-methoxy-butyl)-benzaldehyde (300 mg, 1.35 mmol) and sulfamic acid (176 mg, 1.81 mmol) in 80% acetic acid (2.3 mL) is added dropwise a solution of 80% NaClO2 (127 mg, 1.40 mmol; dissolved in 170 μL of H2O) in water (0.65 mL) over 5 min and by keeping the temperature at 18-20° C. Stirring of the yellow slurry is continued over 3 hrs at 20° C. before adding another aliquot of 80% NaClO2 (151 mg, 1.67 mmol; dissolved in 205 μL of H2O), dissolved in water (0.8 mL), and sulfamic acid (130 mg, 1.34 mmol) in 80% aqueous acetic acid. After stirring overnight, the reaction mixture is diluted by adding water (2.3 mL), the resulting suspension is stirred for 30 min and filtered. The precipitate is dried to give the title product as white solid. TLC, Rf (CH2Cl2/MeOH 98:2)=0.5. MS: 239.0 [M+H]+. 1H-NMR (CD3OD): δ 1.55-1.7 (m, 4H), 2.65 (t, 2H), 3.31 (s, 3H), 3.41 (t, 2H), 3.89 (s, 3H), 4.87 (s, 1H+D2O), 6.98 (m, 1H), 7.78 (s, 1H), 7.87 (m, 1H) ppm.

Provenance & Evidence