3-Fluoroaniline → {4-[(3-Fluoro-phenylamino)-methyl]-2,6-dimethyl-phenyl}-carbamic acid ethyl ester

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Reaction Conditions

Reaction Steps

To (4-formyl-2,6-dimethyl-phenyl)-carbamic acid ethyl ester (230 mg) and 3-fluoroaniline (122 mg) dissolved in dry ethanol (25 mL) was added 3 Å molecular sieves (0.5 g) and the reaction mixture was refluxed for 16 hours under argon. Upon cooling to 25° C., sodium cyanoborohydride (320 mg) and acetic acid (3 mL) were added and stirred for 1 hour. A second batch of sodium cyanoborohydride (320 mg) was added and the mixture stirred for 1 additional hour. Saturated aqueous sodium carbonate (5 mL) was added and the mixture stirred for 1 hour, water (50 mL) was added and the mixture was extracted with ethyl acetate (3×25 mL). The combined organic phases were dried over magnesium sulfate, concentrated in vacuo and purified by flash chromatography to furnish 95 mg (29% yield) of the title compound as a white solid. LC-MS-TOF (m/z) 317 (MH+); tR=3.37, (UV, ELSD) 99%, 96%. 1H NMR (500 MHz, CDCl3): 1.31 (b, 3H), 2.25 (s, 6H), 4.20 (m, 5H), 5.98 (b, 1H), 6.30 (dt, 1H), 6.39 (m, 2H), 7.06 (s, 2H), 7.08 (q, 1H).

Provenance & Evidence