Structures of isororidin E, epoxyisororidin E, and epoxy- and diepoxyroridin H, new metabolites isolated from species determined by carbon-13 and hydrogen-1 NMR spectroscopy. Revision of C2′:C3′ double bond configuration of the roridin group

Absolute Configuration of New Cytotoxic and Other Bioactive Trichothecene Macrolides

“…As a matter of fact, the close resemblance of its 1 H and 13 C NMR spectral data (Dd H = < 0.2 ppm, Dd C = < 1.0 ppm, except for the shift deviation created by the difference in the acyl moieties) with those of roridin E (4) and verrucarin A indicated that metabolite 5 shared with 4 and verrucarin A the same sesquiterpenol residue with its absolute configuration assigned as 2R, 4R, 5S, 6R, 11R, and 12R. [8,17] A close comparison of the 13 C NMR spectra of 5 and 1 demonstrated that the resonance lines from C-1'-C-14' were identical in both sets. This observation substantiated that the absolute configuration of the diacyl moiety was …”

Two New Roridins Isolated from Myrothecium sp.

“…The 12,13-epoxide was suggested by the correlation of the C-13 methylene protons to C-12 and C-2 and the down field chemical shifts of both C-12 and C-13 (8C 65. 6 and 48. indicate the presence of an a,j8-unsaturated ester with a methyl group off the /3-position. Spin system f connects to C-3' by the correlation of the C-4' methylene protons to C-3'.…”

The Use of Carbon-13 Nuclear Magnetic Resonance Spectroscopy in Natural Products Chemistry

“…Two novel guaiane-type diterpenes (421,422) together with pachydictiol A (423) were found in the digestive gland of the sea hare Ap/ysia depilans. Their structures were found to be in accordance with the IJC spectral data.…”