| 摘要 |
<p>A L-alanyl L-proline deriv. of formula (I) and the maleate of its diastereo isomer (S) are made by (1) reaction of the ethyl ester of 2-hydroxy, 4-phenyl butyric acid with sodium hydride in dimethyl formamide at ambient temp., (2) treatment with L-alanyl L-proline protected as trimethyl silyl ester in presence of N,N-methyl phenyl triphenyl phosphonium iodide, (3) filtration and concentration under vacuum, (4) acid treatment and adjustment with alkali to pH 2-3, (5) extraction with chlorinated hydrocarbon solvent, (6) evaporation under vacuum, and (6) isolation of the steric isomer (s) by fractional crystallisation.</p> |
