Silanediol peptidomimetics. Evaluation of four diastereomeric ACE inhibitors

Four diastereomers of a Phe-Ala peptide mimic incorporating a central silanediol group have been individually prepared and tested as inhibitors of angiotensin-converting enzyme (ACE). Three of the silanediols exhibit levels of inhibition that are similar to those of corresponding ketones reported by Almquist. For the fourth diastereomer, with both stereogenic carbons inverted relative to the most active isomer, the ketone gives the least enzyme inhibition whereas the silanediol shows a surprisingly low IC50 value.