title: Synthesis of di- and tripeptide analogues containing alpha-ketoamide as a new core structure for inhibition of HIV-1 protease.
abstract: Di- and tripeptide analogues containing alpha-ketoamide as a new core structure and incorporating allophenylnorstatine (Apns) as a transition state mimic, were designed and synthesized in the hope of obtaining a novel structural type of HIV-1 protease inhibitors. The immediate precursor, Apns-Thz-NHBu(t) was prepared by coupling of Boc-Apns with N-tert x butyl Thz-4-carboxamide hydrochloride. Removal of Boc group followed by coupling with the respective alpha-ketoacid residue (P2) gave the desired dipeptides (8-12) in almost quantitative yields. The alpha-keto tripeptides (18-21) were obtained by oxidation of the hydroxyl group of Apns (PI) in the appropriate tripeptide, iQOA-Val-Apns-(un)substituted Thz(Oxa)-NHBu(t) with DMSO/DCC. Preliminary evaluation of the activity of the synthesized derivatives was determined as percentage of enzyme inhibition at 5 microM and 50 nM levels of the di- and tripeptides respectively. The alpha-ketoamides displayed a significant enhanced potency relative to their parent isosteres as inhibitors of HIV-1 protease and are shown to be a promising new core structure for the development of enzyme inhibitors. A quantitative approach was attempted, using an LFE model, correlating the effect of structural modification and HIV-1 protease inhibition activity of the prepared dipeptides. The result indicates the contribution of the torsion angle by 84% to the activity of the inhibitors.
authors: Department of Pharmaceutical Medicinal Chemistry, Faculty of Pharmacy, Assiut University, Egypt.
authors: M M
authors: MM
authors: Sheha
authors: N M
authors: NM
authors: Mahfouz
authors: H Y
authors: HY
authors: Hassan
authors: A F
authors: AF
authors: Youssef
authors: T
authors: T
authors: Mimoto
authors: Y
authors: Y
authors: Kiso
mesh_terms: D000577:Amides / Q000737:chemistry*; D019380:Anti-HIV Agents / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D017320:HIV Protease Inhibitors / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*; D015497:HIV-1 / Q000187:drug effects / Q000201:enzymology; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D008826:Microbial Sensitivity Tests; D015394:Molecular Structure; D009842:Oligopeptides / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*; D013329:Structure-Activity Relationship
chemical_list: D000577:Amides; D019380:Anti-HIV Agents; D017320:HIV Protease Inhibitors; D009842:Oligopeptides