反应详情

温度

0 °C

A solution of 1.12 g (5.56 mmol) of 4-nitrophenyl chloroformate in 20 ml of CH2Cl2 was cooled to 0° C. and treated sequentially with 0.8 g (5.1 mmol) of 4-(hydroxymethyl)-2-isopropylthiazole and 0.6 ml (5.6 mmol) of 4-methylmorpholine. The resulting solution was stirred at 0° C. for 1 h, diluted with CH2Cl2, washed with three portions of aqueous NaHCO3, dried over Na2SO4, and concentrated in vacuo to give crude 2-isopropyl-4-(p-nitrophenyloxycarbonyloxymethyl)thiazole. A portion (0.53 g, 1.65 mmol) of the residue was taken up in 20 ml of chloroform, treated with 0.23 g (1.67 mmol) of L-alanine methyl ester hydrochloride and 0.36 ml (3.3 mmol) of 4-methylmorpholine, and heated at reflux for 16 h. After being allowed to cool, the solven was removed in vacuo, and the residue was purified by silica gel chromatography using 2% methanol in chloroform to provide 0.45 g (94%) of the desired compound, Rf 0.43 (5% methanol in CH2Cl2). 1H NMR (DMSO-d6) δ1.26 (d, J=8 Hz, 3H), 1.32 (d, J=7 Hz, 6H), 3.27 (heptet, J=7 Hz, 1H), 3.63 (s, 3H), 4.10 (p, J=8 Hz, 1H), 5.02 (s, 2H), 7.47 (s, 1H), 7.81 (d, J=8 Hz, 1H). Mass spectrum: (M+H)+ =287.

1. washwashed with three portions of aqueous NaHCO3
2. dry with materialdried over Na2SO4
3. concentrationconcentrated in vacuo