Pyridine → cis-4-benzyloxycarbonylamino-2-ethyl-6-trifluoromethyl-3,4-dihydro-2H-quinoline-1-carboxylic acid ethyl ester

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Reaction Steps

A solution of cis-(2-ethyl-6-trifluoromethyl-1,2,3,4-tetrahydro-quinolin4-yl)-carbamic acid benzyl ester (Example 3B) (37.0 g, 97.9 mmol) and pyridine (23.2 g, 293.7 mmol) in dichloromethane (1 L) was cooled in an ice/water bath as ethyl chloroformate (37.2 g, 342.6 mmol) was added slowly. After stirring at room temperature overnight, the mixture was cooled with an ice/water bath as a 1M potassium hydroxide solution was added to quench the reaction. The organic phase was washed twice with a 2M hydrochloric acid solution, dried over magnesium sulfate, filtered and concentrated in vacuo to afford the crude product which was purified by silica gel chromatography using 10-15% ethyl acetate/hexanes as eluent to afford 40 g of the title product. 1H NMR (CDCl3) δ 0.83 (t, 3H), 1.28 (t, 3H), 1.4-1.6 (m, 3H), 2.53 (m, 1H), 4.23 (m, 2H), 4.47 (m, 1H), 4.80 (m, 1H), 4.94 (m, 1H), 5.18 (s, 2H), 7.3-7.6 (m, 8H).

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