| 摘要 |
<p>Prodn. of the proline of formula (I) comprises (1) reacting ethyl 2-oxo-4-phenylbutyrate and L-alanine to give cpd. (II); (2) reacting (II) with N-hydroxysuccinimide (HSU) in presence of DCC to form the ester (III) which (3) is reacted with L-proline in presence of base, e.g. The first step is in presence of a reducing agent (e.g. NaBH3CN or H2-catalyst) and a drying agent (e.g. 4A molecular sieve) in polar solvent, e.g. acetic acid and/or EtOH. The second step is in a polar solvent, e.g. 1,2-dimethoxyethlane and THF, and the last step is in a mixt. of the same solvents with water.</p> |
