反应详情

The product of N-pyrazineformyl-L-phenylalanyl-L-phenylalanine methyl ester (1.52 g, 3.52 mmol) in Preparation example 4 was dissolved with 10 ml of acetone, 2N NaOH was added dropwise slowly under the condition of ice water bath until a pH value of 12˜13 was obtained, and the solution was kept reacting under the condition of an ice water bath, the reaction was monitored by TLC and completed after 2 h. Hydrochloric acid was added dropwise under the condition of ice water bath until a pH value of 2˜3 was obtained, a large amount of white solid was produced, the generated precipitate was filtered, washed with diethyl ether followed by airing to dry, 1.33 g of white product was obtained with a yield of 90.5%, the melting point of the white solid: 194-196° C.; 1H-NMR (DMSO-d6, 300 MHz): δ 12.88 (s, 1H), 9.10 (s, 1H), 8.90-8.87 (m, 1H), 8.77-8.73 (m, 1H), 8.75-8.65 (m, 2H), 7.24-7.14 (m, 10H), 4.84-4.80 (m, 1H), 4.53-4.50 (m, 1H), 3.14-2.89 (m, 4H).

1. additionwas added dropwise slowly under the condition of ice water bath until a pH value of 12˜13
2. customwas obtained
3. customthe solution was kept reacting under the condition of an ice water bath
4. customwas obtained
5. customa large amount of white solid was produced
6. filtrationthe generated precipitate was filtered
7. washwashed with diethyl ether
8. customto dry