反应详情

温度

0 °C

N-Methyl-L-glutamic acid (3.2 g) was added to water (50 ml) and the pH of the solution adjusted to 9 with solid sodium bicarbonate. The solution was cooled to 0° C. and stirred vigorously, while benzyl chloroformate (9 ml) was added dropwise over 20 min. The mixture was stirred for a further 2 h at 0° C. and an additional 2 h at room temperature, then extracted with diethyl ether (2×100 ml). The aqueous solution was then acidified to pH 3 with 5N HCl and the product isolated by extraction with ethyl acetate (2×100 ml). The pooled organic extracts were dried over anhydrous sodium sulphate and the solvent concentrated in vacuo to give a yellow oil, which crystallised on standing. Recrystallisation from water afforded N-(benzyloxycarbonyl)-N-methyl-L-glutamic acid (2.26 g), m.p. 97°-98° C.

1. additionwas added dropwise over 20 min
2. extractionextracted with diethyl ether (2×100 ml)
3. customthe product isolated by extraction with ethyl acetate (2×100 ml)
4. dry with materialThe pooled organic extracts were dried over anhydrous sodium sulphate
5. concentrationthe solvent concentrated in vacuo
6. customto give a yellow oil, which
7. customcrystallised
8. customRecrystallisation from water