A mixture of 2.4 g of 6-(2-methoxyphenyl)-2,2,4-trimethyl-1,2-dihydroquinoline (see Example 1) in 35 mL of CH2Cl2 was cooled down to −78° C. To this mixture, 13.1 mL of 1.6 M n-BuLi in hexane was added dropwise. The mixture was warmed to 0° C. and 2.9 g of (di-tert-butyl)carbonate was added. The mixture was allowed to stir at 0° C. for 1 hour. The reaction was then worked up by adding water and extracting with EtOAc three times. The organic layers were combined, washed sequentially with 1 N HCl, water, saturated aqueous sodium bicarbonate solution, water, saturated aqueous NaCl solution, dried over magnesium sulfate, and the solvent evaporated in vacuo. The residue was purified by flash chromatography to yield 1.4 g of 6-(2-methoxyphenyl)-2,2,4-trimethyl-2H-quinoline-1-carboxylic acid tert-butyl ester as a solid.
