Acetic Acid → cis-4-[(3,5-Bis-trifluoromethyl-benzyl)-amino]-6,7-dimethoxy-2-methyl-3,4-dihydro-2H-quinoline-1-carboxylic acid ethyl ester

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Reaction Steps

A solution of cis-4-amino-6,7-dimethoxy-2-methyl-3,4-dihydro-2H-quinoline-1-carboxylic acid ethyl ester (527 mg, 1.8 mmol) in dichloroethane (12 mL) was treated sequentially with acetic acid (0.1 mL, 1.8 mmol) and 3,5-bis-trifluoromethyl-benzaldehyde (0.30 mL, 1.8 mmol). After stirring 35 minutes at room temperature, sodium triacetoxyborohydride (570 mg, 2.7 mmol) was added to the mixture. After 3 days, 20 mL of water was added and the mixture made basic (pH 10) with potassium carbonate. The mixture was extracted with ethyl acetate (3×35 mL), the combined organic layers were washed with brine (20 mL), dried over sodium sulfate, filtered, and concentrated in vacuo. The residue was purified by silica gel chromatography eluting with 0-20% ethyl acetate in hexanes to provide the title compound (663 mg). 1H NMR (CDCl3) δ 1.22 (d, 3H), 1.3 (t, 3H), 1.5 (m, 1H), 2.6 (m, 1H), 3.55 (dd, 1H), 3.87 (s, 3H), 3.89 (s, 3H), 4.1-4.6 (m, 5H), 7.06 (s, 1H), 7.08 (s, 1H), 7.8 (s, 1H), 7.95 (s, 2H).

Provenance & Evidence