title: Total synthesis and initial structure-function analysis of the potent V-ATPase inhibitors salicylihalamide A and related compounds.
abstract: Salicylihalamide A is the first member of a growing class of macrocyclic salicylate natural products that induce a variety of interesting phenotypes in cultured mammalian cells. Salicylihalamide A was reported to be a unique and highly differential cytotoxin and a potent inhibitor of the mammalian vacuolar (H(+))-ATPase. The total synthesis of both enantiomers of salicylihalamide A, a revision of the absolute configuration assigned to the natural product, and extensive structure-function studies with synthetic salicylihalamide variants are reported. These studies were possible only due to a highly efficient synthetic strategy that features (1) a remarkably E-selective ring-closing olefin metathesis to construct the 12-membered benzolactone skeleton 29, (2) a mild stereocontrolled elaboration to E-alkenyl isocyanate 41, and (3) addition of carbon, oxygen, and sulfur nucleophiles to isocyanate 41 to obtain salicylihalamide A and congeners. We demonstrate for the first time that salicylihalamide A is a potent inhibitor of fully purified reconstituted V-ATPase from bovine brain, and have identified several similarly potent side chain modified derivatives, including salicylihalamide dimers 43-45. In combination, these studies have laid the foundation for ongoing studies aimed at a comprehensive understanding of salicylihalamide's mode-of-action, of potential relevance to the development of lead compounds for the treatment of osteoporosis and cancer.
authors.affiliation: Department of Biochemistry, The University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Boulevard, Dallas, TX 75390-9038, USA.
authors.forename: Yusheng
authors.initials: Y
authors.lastname: Wu
authors.forename: Xibin
authors.initials: X
authors.lastname: Liao
authors.forename: Ruifang
authors.initials: R
authors.lastname: Wang
authors.forename: Xiao-Song
authors.initials: XS
authors.lastname: Xie
authors.forename: Jef K
authors.initials: JK
authors.lastname: De Brabander
mesh_terms: D000970:Antineoplastic Agents / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D013329:Structure-Activity Relationship; D025262:Vacuolar Proton-Translocating ATPases / Q000037:antagonists & inhibitors*
chemical_list: D000970:Antineoplastic Agents; D019086:Bridged Bicyclo Compounds, Heterocyclic; D004791:Enzyme Inhibitors; C410986:salicylihalamide A; D025262:Vacuolar Proton-Translocating ATPases