反应详情

To a solution of 2-methyl-terephthalic acid 1-methylester (preparation see WO 2000/021920) (1.43 g) in dichloromethane (10 ml) was added N-(−3-dimethylaminopropyl)-N′-ethylcarbodiimid hydrochloride (1.84 g), N,N-dimethylaminopyridine (0.41 g) and trimethylsilylmethylamine (1 ml). The reaction mixture was stirred at ambient temperature. for 2 hours. The reaction mixture was concentrated and the residue purified by chromatography on silica gel (eluent: ethyl acetate/heptanes 1:3) to give 2-methyl-N-trimethylsilanylmethyl-terephthalamic acid methyl ester (1.85 g). 1H-NMR (400 MHz, CDCl3): 7.72 (d, 1H), 7.45 (s, 1H), 7.40 (d, 1H), 5.85 (s, 1H), 3.78 (s, 3H), 2.84 (d, 2H), 2.49 (s, 3H), 0.00 (s, 9H) ppm. 2-Methyl-N-trimethylsilanylmethyl-terephthalamic acid tert-butyl ester was obtained using a similar procedure. 1H-NMR (400 MHz, CDCl3): 7.82 (d, 1H), 7.48 (s, 1H), 7.39 (d, 1H), 5.70 (s, 1H), 2.82 (d, 2H), 2.48 (s, 3H), 1.48 (s, 9H), 0.00 (s, 9H) ppm.

1. concentrationThe reaction mixture was concentrated
2. customthe residue purified by chromatography on silica gel (eluent: ethyl acetate/heptanes 1:3)