反应详情

A solution of 12.3 g of Z-β-Ala-OH and 16.0 g of H-His-OCH3 ×2 HCl in 300 ml of DMF is cooled to 0° and there are added dropwise thereto first a solution of 22.75 g of phosphoric acid diphenyl ester azide in 110 ml of DMF and then a solution of 30.7 ml of triethylamine in 110 ml of DMF. The suspension so obtained is stirred for 2 days at room temperature and then concentrated to an oily suspension in a high vacuum. The residue is taken up in ethyl acetate, washed with sodium bicarbonate and brine, dried and concentrated by evaporation. The crude product is separated by flash chromatography (1.6 kg of silica gel [type 60, Merck], 40-63 μm, 0.4 bar, fractions of 400 ml, eluant: CH2Cl2 /MeOH[13:2]). By concentration by evaporation of the appropriate fractions, Z-β-Ala-His-OCH3 is obtained as a slightly yellowish foam; Rf (L)=0.69.

1. additionthere are added dropwise
2. customThe suspension so obtained
3. concentrationconcentrated to an oily suspension in a high vacuum
4. washwashed with sodium bicarbonate and brine
5. customdried
6. concentrationconcentrated by evaporation
7. customThe crude product is separated by flash chromatography (1.6 kg of silica gel [type 60, Merck], 40-63 μm, 0.4 bar, fractions of 400 ml, eluant: CH2Cl2 /MeOH[13:2])
8. concentrationBy concentration
9. customby evaporation of the appropriate fractions