title: Design and synthesis of acyclic triaryl (Z)-olefins: a novel class of cyclooxygenase-2 (COX-2) inhibitors.
abstract: A group of acyclic 2-alkyl-1,1-diphenyl-2-(4-methylsulfonylphenyl)ethenes was designed for evaluation as selective cyclooxygenase-2 (COX-2) inhibitors. In vitro COX-1 and COX-2 isozyme inhibition structure-activity studies identified 1,1-diphenyl-2-(4-methylsulfonylphenyl)hex-1-ene as a highly potent (IC(50) = 0.014 microM), and an extremely selective [COX-2 selectivity index (SI) > 7142], COX-2 inhibitor that showed superior anti-inflammatory (AI) activity (ID(50) = 2.5 mg/kg) relative to celecoxib (ID(50) = 10.8 mg/kg). This initial study was extended to include the design of a structurally related group of acyclic triaryl (Z)-olefins possessing an acetoxy (OAc) substituent at the para-position of the C-1 phenyl ring that is cis to a C-2 4-methylsulfonylphenyl substituent. COX-1 and COX-2 inhibition studies showed that (Z)-1-(4-acetoxyphenyl)-1-phenyl-2-(4-methylsulfonylphenyl)but-1-ene [(Z)-13b] is a potent (COX-1 IC(50) = 2.4 microM; COX-2 IC(50) = 0.03 microM), and selective (COX-2 SI = 81), COX-2 inhibitor which is a potent AI agent (ID(50) = 4.1mg/kg) with equipotent analgesic activity to celecoxib. A molecular modeling (docking) study showed that the SO(2)Me substituent of (Z)-13b inserts deep inside the 2 degrees -pocket of the COX-2 active site, where one of the O-atoms of SO(2) group undergoes a H-bonding interaction with Phe(518). The p-OAc substituent on the C-1 phenyl ring is oriented in a hydrophobic pocket comprised of Met(522), Gly(526), Trp(387), Tyr(348), and Tyr(385), and the C-2 ethyl substituent is oriented towards the mouth of the COX-2 channel in the vicinity of amino acid residues Arg(120), Leu(531), and Val(349). Structure-activity data acquired indicate that a (Z)-olefin having cis C-1 4-acetoxyphenyl (phenyl) and C-2 4-methylsulfonylphenyl substituents, and a C-1 phenyl substituent in conjunction with either a C-2 hydrogen or short alkyl substituent provides a novel template to design acyclic olefinic COX-2 inhibitors that, like aspirin, have the potential to acetylate COX-2.
authors.affiliation: Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, Alberta, Canada T6G 2N8.
authors.forename: Md Jashim
authors.initials: MJ
authors.lastname: Uddin
authors.forename: P N Praveen
authors.initials: PN
authors.lastname: Rao
authors.forename: Edward E
authors.initials: EE
authors.lastname: Knaus
mesh_terms: D000475:Alkenes / Q000138:chemical synthesis* / Q000494:pharmacology / Q000627:therapeutic use; D000818:Animals; D051546:Cyclooxygenase 2; D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors / Q000138:chemical synthesis* / Q000494:pharmacology / Q000627:therapeutic use; D015195:Drug Design; D004487:Edema / Q000188:drug therapy / Q000201:enzymology; D008297:Male; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012756:Sheep
chemical_list: D000475:Alkenes; D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors; D051546:Cyclooxygenase 2; D011451:Prostaglandin-Endoperoxide Synthases