反应详情

温度

-70 °C

Trifluoromethanesulfonic anhydride (10.00 g, 0.0354 mol) and dry methylene chloride (60 ml) were placed into a 500 ml separable flask having its interior atmosphere replaced with well dried nitrogen gas, and cooled to -70° C. Then a solution of 3-methyl-4-nitrobenzyl alcohol (5.34 g, 0.0325 mol) and N,N-diisopropylethylamine (6.2 ml, 0.0356 mol) in dry methylene chloride (40 ml) was added dropwise over a period of 15 minutes, followed by stirring for 30 minutes, after which a solution of N,1-bis-t-butoxycarbonyl-L-histidine methyl ester (XI-2) (10.00 g, 0.0271 mol) in dry methylene chloride (40 ml) was further added dropwise over a period of 20 minutes. Thereafter, the reaction flask was taken out of the cooling bath and the mixture was stirred at room temperature for 6 hours. The reaction mixture during rapid stirring was poured into a 0.2M phosphate buffer solution (about 400 ml) to separate the methylene chloride layer, and the residue was washed with a 0.2M phosphate buffer solution (about 400 ml), dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure to obtain an orange-colored oily material (12.07 g). This crude oily material was purified by silica gel column chromatography (LiChroprep Si60, 300 g, chloroform/methanol=30/1) to obtain the objective compound (IX-2) (4.45 g; yield: 39.3%) as a light-yellow oily material.

1. stirringthe mixture was stirred at room temperature for 6 hours
2. stirringThe reaction mixture during rapid stirring
3. customto separate the methylene chloride layer
4. washthe residue was washed with a 0.2M phosphate buffer solution (about 400 ml)
5. dry with materialdried over anhydrous sodium sulfate
6. filtrationfiltered
7. concentrationconcentrated under reduced pressure