PROCESS FOR PREPARING SUBSTITUTED WAROYE(PROPIONYL OR BUTYRYL)-L-PROLINES

Title compds. I (R3=mercapto, formylthio, benzoylthio, C2˜C4 alkanoylthio; R4=H, Ph, C1˜C4 alkyl; R5=H C1˜C4 alkyl)were prepd. as hypotensives; they inhibited angiotensinconverting enzyme (ACE). Thus, 165mL dioxane soln. contg. 26.4g benzoyl acrylate and 17.25g N-hydroxysuccinimide was treated with 30.9g dicyclohexylcarbodiimide in 120mL dioxane at room temp. for 18 hrs. to give 18.2g hydroxysuccinimide. ester of benzoylacrylate, which was reacted with 7.71g L-proline and 11.26g NaHCO3 to give 10.1g 1-(3-benzoylacryloyl)-L- ! proline. The resulting product was treated with thioactic acid and CCl4 to give 1-(2-acetylthio-3-benzoylpropionyl)-L-proline.