title: New cytotoxic 1,2,4-thiadiazole alkaloids from the ascidian Polycarpa aurata.
abstract: Two new alkaloids, polycarpathiamines A and B (1 and 2), were isolated from the ascidian Polycarpa aurata. Their structures were unambiguously determined by 1D, 2D NMR, and HRESIMS measurements and further confirmed by comparison with a closely related analogue, 3-dimethylamino-5-benzoyl-1,2,4-thiadiazole (4), that was prepared by chemical synthesis. Compounds 1 and 2 both feature an uncommon 1,2,4-thiadiazole ring whose biosynthetic origin is proposed. Compound 1 showed significant cytotoxic activity against L5178Y murine lymphoma cells (IC50 0.41 μM).
authors.affiliation: Institute of Pharmaceutical Biology and Biotechnology, Heinrich-Heine University, 40225 Düsseldorf, Germany.
authors.forename: Cong-Dat
authors.initials: CD
authors.lastname: Pham
authors.forename: Horst
authors.initials: H
authors.lastname: Weber
authors.forename: Rudolf
authors.initials: R
authors.lastname: Hartmann
authors.forename: Victor
authors.initials: V
authors.lastname: Wray
authors.forename: Wenhan
authors.initials: W
authors.lastname: Lin
authors.forename: Daowan
authors.initials: D
authors.lastname: Lai
authors.forename: Peter
authors.initials: P
authors.lastname: Proksch
mesh_terms: D000470:Alkaloids / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*; D000818:Animals; D004354:Drug Screening Assays, Antitumor; D051379:Mice; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D013830:Thiadiazoles / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*; D014561:Urochordata / Q000737:chemistry*
chemical_list: C583654:3-dimethylamino-5-benzoyl-1,2,4-thiadiazole; D000470:Alkaloids; D013830:Thiadiazoles; C583652:polycarpathiamine A; C583653:polycarpathiamine B