Acetic Acid → cis-4-(3,5-bis-trifluoromethyl-benzylamino)-2-ethyl-6-trifluoromethyl-3,4-dihydro-2H-quinoline-1-carboxylic acid ethyl ester

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Reaction Steps

A solution of cis-4-amino-2-ethyl-6-trifluoromethyl-3,4-dihydro-2H-quinoline-1-carboxylic acid ethyl ester (Example 3D) (8.8 g, 27.8 mmol) was treated sequentially with acetic acid (5.0 g, 83.5 mmol), 3,5-bis-trifluoromethyl-benzaldehyde (6.74 g, 27.8 mmol), followed by sodium triacetoxyborohydride (29.5 g, 139.2 mmol). After stirring at room temperature for 24 h, the mixture was combined with 500 mL of 1M potassium hydroxide, and the aqueous layer was extracted with dichloromethane (2×200 mL). The combined organic phases were dried over magnesium sulfate, filtered and concentrated in vacuo to afford the crude product, which was purified by silica gel chromatography using 5-10% ethyl acetate/hexanes as eluent to afford 13.8 g of the title product. 1H NMR (CDCl3) δ 0.85 (t, 3H), 1.27 (m, 4H), 1.45 (m, 2H), 1.67 (m, 1H), 2.66 (m, 1H), 3.56 (m, 1H), 4.1-4.3 (m, 4H), 4.42 (m, 1H), 7.49 (d, 1H, J=8.5 Hz), 7.52 (d. 1H, J=8.5 Hz), 7.76 (s, 1H), 7.79 (s, 1H), 7.91 (s, 2H).

Provenance & Evidence