title: Outer-ring stereochemical modulation of cytotoxicity in cephalostatins.
abstract: [structure: see text] 20- and 25'-epimers of cephalostatin 7, prepared by directed unsymmetrical pyrazine synthesis, address outer-ring topographical and stability questions and intimate an oxacarbenium ion rationale for the role in bioactivity of the spiroketal (E/F, E'/F') rings of this class of antitumor agents.
authors.affiliation: Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, USA. lacour@purdue.edu
authors.forename: T G
authors.initials: TG
authors.lastname: LaCour
authors.forename: C
authors.initials: C
authors.lastname: Guo
authors.forename: M R
authors.initials: MR
authors.lastname: Boyd
authors.forename: P L
authors.initials: PL
authors.lastname: Fuchs
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000138:chemical synthesis* / Q000633:toxicity; D006801:Humans; D051379:Mice; D008958:Models, Molecular; D008968:Molecular Conformation; D015394:Molecular Structure; D009369:Neoplasms / Q000188:drug therapy; D010619:Phenazines / Q000138:chemical synthesis* / Q000633:toxicity; D013141:Spiro Compounds / Q000138:chemical synthesis*; D013256:Steroids
chemical_list: D000970:Antineoplastic Agents; D010619:Phenazines; D013141:Spiro Compounds; D013256:Steroids; C409226:cephalostatin 7; C086772:cephalostatin 10