The structure of a 2-deoxystreptamine (DOS) precursor named S-11-P, which was isolated by using a DOS negative mutant derived from a xylostasin-producing strain of Bacillus circulans B15M, has been elucidated as (1 L)-1,3,5/2,4,-5-aminocyclohexanetetrol by comparison with an authentic specimen, which was synthesized from kanamycin A.

Tannins and related polyphenols have been reported to produce diverse biological effects that indicate their therapeutic potential, including antioxidative, antibacterial, and antiviral activities. In an exploratory study of natural antioxidants with biological effects, we investigated the tannin constituents of myrtaceous plants reported to be rich in polyphenols. We isolated 16 new compounds ...

Nigricanoside A was isolated from green alga, and its dimethyl ester was found to display potent cytotoxicity. Its scarcity prevented a full structure elucidation, leaving total synthesis as the only means to determine its relative and absolute stereochemistry and to explore its biological activity. Here we assign the stereochemistry of the natural product through enantioselective total synthes...

A hexachloro congener (Q1-hex) of the natural heptachloro-1'-methyl-1,2'-bipyrrole Q1 was recently observed as a byproduct of the Q1 synthesis. NMR investigation confirmed that Q1-hex has a proton on a carbon in beta-position to a nitrogen. Three isomers are possible that fulfill this prerequisite; unfortunately, however, the NMR data were not sufficient to distinguish among the three structura...

We present a novel application of ILP to the problem of diterpene structure elucidation from 13 C NMR spectra. Diterpenes are organic compounds of low molecular weight that are based on a skeleton of 20 carbon atoms. They are of signiicant chemical and commercial interest because of their use as lead compounds in the search for new pharmaceutical eeectors. The structure elucidation of diterpene...

The genus Salvia is a valuable origin of structurally diverse terpenoids. In a project directed at structurally interesting bioactive metabolites from Iranian Salvia species, we studied Salvia reuterana. Two new labdane diterpene, 6β,14α-dihydroxy-15-acetoxysclareol (1), and 14α,15- dihydroxy sclareol (2), were isolated from the aerial part of the plant. Their structures were established mainly...