反应详情

To a solution of 154 mg of N-[(+)-2-(1-naphthylmethyl)-3-(phenethylcarbamoyl)propionyl]-L-histidine hydrazide in 4 ml of N,N-dimethylformamide were added successively dropwise 0.19 ml of a dry 5.1N-hydrogen chloride in N,N-dimethylformamide solution and 0.05 ml of isoamyl nitrite at -20° C., and the mixture was stirred. After disapperance of hydrazide compound, the reaction mixture was cooled to -30° C., and neutralized by adding 0.14 ml of triethylamine to prepare a solution of N-[(+)-2-(1-naphthylmethyl)-3-(phenethylcarbamoyl)propionyl]-L-histidine azide. The azide solution prepared was added dropwise to a solution of 64 mg of methyl (2RS, 3S)-3-amino-2-hydroxy-5-methylhexanoate hydrochloride and 0.09 ml of triethylamine in 2 ml of N,N-dimethylformamide under ice-cooling, and the mixture was stirred for 16 hours under ice-cooling. A 5% aqueous sodium bicarbonate solution was added to the reaction mixture, and the mixture was extracted with ethyl acetate. The ethyl acetate layer was washed with a saturated sodium chloride aqueous solution, dried over anhydrous magnesium sulfate, and evaporated under reduced pressure. The residue was purified by silica gel flash column chromatography (eluent: chloroform/methanol=10/1 by volume) to obtain 120 mg of methyl (2RS, 3S)-3-{N-[(+)-2-(1-naphthylmethyl)-3-(phenethylcarbamoyl)propionyl]-L-histidyl}amino-2-hydroxy-5-methylhexanoate as a white powder.

1. temperaturecooling
2. temperaturecooling
3. extractionthe mixture was extracted with ethyl acetate
4. washThe ethyl acetate layer was washed with a saturated sodium chloride aqueous solution
5. dry with materialdried over anhydrous magnesium sulfate
6. customevaporated under reduced pressure
7. customThe residue was purified by silica gel flash column chromatography (eluent: chloroform/methanol=10/1 by volume)