Libraries of ACE inhibitors were prepared by solid-phase methods involving reductive alkylation of resin-bound dipeptides, H-X-Pro-DHPP-PEG-PS or H-X-X-PAL-PEG-PS. Affinity selection of the library components identified hydrophilic N-alkylated dipeptides as potential inhibitors. (C) 1997 Elsevier Science Ltd.