Benzylamine → 4-Benzylimino-6,7-dimethoxy-2-methyl-3,4-dihydro-2H-quinoline-1-carboxylic acid benzyl ester

Participants

Reaction Steps

6,7-Dimethoxy-2-methyl-4-oxo-3,4-dihydro-2H-quinoline-1-carboxylic acid benzyl ester (0.83 g, 2.3 mmol) was dissolved in a solution of triethylamine (2.2 mL, 2.3 mmol), benzylamine (0.55 mL, 5.1 mmol), and anhydrous dichloromethane (15 mL). This solution was stirred in a room temperature water bath as 2.5 mL of 1M solution of titanium tetrachloride (TiCl4) in dichloromethane (2.5 mmol) was slowly added. The reaction was allowed to stir at room temperature for 48 h. The reaction mixture was then poured into a stirred solution of water (50 mL) and potassium carbonate (10 g). After filtration, the filtrate was extracted with ethyl acetate (3×100 mL), the combined organic phases washed with water (100 mL), brine (50 mL), dried over sodium sulfate, filtered, and concentrated in vacuo to give the desired imine (1.12 g, ca. 100%). 1H NMR (CDCl3) δ 1.2 (d, 3H), 2.7-2.9 (m, 2H), 3.7 (s, 3H), 3.9 (s, 3H), 4.6 (d, 1H), 4.7 (d, 1H), 5.0-5.2 (m, 2H), 5.4 (d, 1H), 7.2-7.5 (m, 11H), 7.8 (s, 1H).

Provenance & Evidence