Synthesis and pharmacological screening of new angiotensin converting enzyme inhibitors.

We report the preparation of a series of eight L-alanyl-L-proline derivatives and four L-proline derivatives. Their pharmacological activity as antihypertensive agents was examined with reference to changes in the contractile response to angiotensin I (AI), bradykinine (BK) and angiotensin II (AII). Compounds 1g, 1h and 2c were the most powerful when compared with known angiotensin-converting inhibitors such as captopril and enalapril, and were selected for further pharmacological study.