title: Identification, synthesis, and conformation of tri- and tetrathiacycloalkanes from marine bacteria.
abstract: Seven new cyclic natural polysulfides 1-7 were identified in extracts of two bacterial Cytophaga strains (CFB-phylum) isolated from biofilms from the North Sea. Their structures are based on mono- and dimeric-cyclization products of 2-methylpropane-1,2-dithiol 8, which was also present in the extract in trace amounts. The structures were deduced by analysis of their mass spectra and confirmed by synthesis. The 1H NMR spectra of some these compounds suggested a high flexibility of the trithiepane and tetrathiocane systems. Therefore, their conformation was further analyzed by DFT calculations and dynamic NMR spectroscopy. While thiepane 4 possesses a twist-chair lowest energy conformation, its isomers 2 and 3 adopt a chairlike conformation, as does the tetrathiocane 5. In contrast, tetrathiocane 6 favors again a twisted chair conformation.
authors.affiliation: Institut für Organische Chemie, Technische Universität Braunschweig, Germany.
authors.forename: Paul
authors.initials: P
authors.lastname: Sobik
authors.forename: Jörg
authors.initials: J
authors.lastname: Grunenberg
authors.forename: Katalin
authors.initials: K
authors.lastname: Böröczky
authors.forename: Hartmut
authors.initials: H
authors.lastname: Laatsch
authors.forename: Irene
authors.initials: I
authors.lastname: Wagner-Döbler
authors.forename: Stefan
authors.initials: S
authors.lastname: Schulz
mesh_terms: D002849:Chromatography, Gas; D003516:Cycloparaffins / Q000138:chemical synthesis* / Q000737:chemistry; D003589:Cytophaga / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D008958:Models, Molecular; D008968:Molecular Conformation; D009659:North Sea; D013438:Sulfhydryl Compounds / Q000737:chemistry*
chemical_list: D003516:Cycloparaffins; D013438:Sulfhydryl Compounds