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Seven new cyclic natural polysulfi
des
1-7 were i
dentifie
d in extracts of two bacterial
Cytophaga strains(CFB-phylum) isolate
d from biofilms from the North Sea. Their structures are base
d on mono- an
d dimeric-cyclization pro
ducts of 2-methylpropane-1,2-
dithiol
8, which was also present in the extract in traceamounts. The structures were
de
duce
d by analysis of their mass spectra an
d confirme
d by synthesis. The
1H NMR spectra of some these compoun
ds suggeste
d a high flexibility of the trithiepane an
d tetrathiocanesystems. Therefore, their conformation was further analyze
d by DFT calculations an
d dynamic NMRspectroscopy. While thiepane
4 possesses a twist-chair lowest energy conformation, its isomers
2 an
d 3a
dopt a chairlike conformation, as
does the tetrathiocane
5. In contrast, tetrathiocane
6 favors again atwiste
d chair conformation.
