反应详情

温度

0 °C

A mixture of 3-(ethoxycarbonyl)-2-(2-methylpropyl)butanoic acid (7.5 g., 0.037 mol.) and dichloromethane (70 mls.) was stirred and cooled to 0° C. To the mixture was added dropwise a solution of N,N'-dicyclohexylcarbodiimide (7.6 g., 0.37 mol.) in dichloromethane (20 mls.) and the reaction mixture was allowed to warm to room temperature. A solution of O-methyl-L-tyrosine N-methylamide (7.7 g., 0.037 mol.) in dichloromethane (45 mls.) was added to the reaction mixture and the resulting mixture was stirred overnight at room temperature. A saturated sodium bicarbonate solution (100 mls.) was added to the reaction mixture and the resulting mixture was stirred for an additional hour. The reaction mixture was filtered and the organic layer recovered and then dried over anhydrous sodium sulfate. The solvent was removed by evaporation in vacuo to yield a sticky brown solid. Th solid was purified by chromatography on normal phase silica eluting with 20% hexane in ethyl acetate to yield N-[3-(ethoxycarbonyl)-2-(2-methylpropyl)butanoyl]-O-methyl-L-tyrosine N-methylamide as a mixture of 4 diastereomers.

1. temperatureto warm to room temperature
2. stirringthe resulting mixture was stirred overnight at room temperature
3. stirringthe resulting mixture was stirred for an additional hour
4. filtrationThe reaction mixture was filtered
5. customthe organic layer recovered
6. dry with materialdried over anhydrous sodium sulfate
7. customThe solvent was removed by evaporation in vacuo
8. customto yield a sticky brown solid
9. customTh solid was purified by chromatography on normal phase silica eluting with 20% hexane in ethyl acetate