L-alanyl-L-proline derivs. prepn. - by reacting deriv. of proline and ethyoxy-carbonyl phenyl-proyl-L alanine

摘要

Prodn. of L-alanyl-L-proline derivs. of formula (I), where R is ethyl or hydrogen, or their pharmaceutically acceptable salts, involves reacting derivs. of proline and N(1(S)-ethoxycarbonyl- 3-phenylpropyl)- L-alanine in solvent at (-5) to (20) deg.C. The proline deriv. comprises N-O-bis-trimethylsilyl- L-proline of formula (II). The deriv. of N(1(S)-ethoxycarbonyl- 3-phenyl-propyl)- L-alamine has formula (III), where Het is imidazolyl-1 or benzothiazolyl-2-thio. The condensn. reaction is carried out in non-polar organic solvent, esp. in dioxane, tetrahydrofuran or methylene chloride. When required, the obtd. cpd. of formula (I) in which R is ethyl is hydrolysed to obtain a cpd. of formula (I) in which R is hydrogen. Yield is 76%; m.pt. is 146-152 deg.C. When the maleate is required, a cpd. of formula (I) in which R is ethyl is treated with maleic acid. Yield is 83% and m.pt. is 143-147 deg.C.