Artificial networks can be used to identify hydrogen nuclear magnetic resonance (1H-NMR) spectra of complex oligosaccharides. Feed-forward neural networks with back-propagation of errors can distinguish between spectra of oligosaccharides that differ by only one glycosyl residue in twenty. The artificial neural networks use features of the strongly overlapping region of the spectra (hump region...

Four new C-glucopyranosides of resveratrol oligomers, hemsleyanosides A-D, were isolated from the bark of Shorea hemsleyana. The structures were established on the basis of spectroscopic evidence, including 1H-1H and 1H-13C long-range couplings and nuclear Overhauser effect experiments in the NMR spectrum.

schiff base sal-2,5-clan = 2-(2,5-dichlorobenzylideneamino)phenol used as a new precursor for preparation of poly-2-(2,5-dichlorobenzylideneamino)phenol (pdcbap). in an aqueous alkaline medium, naocl oxidant is capable of oxidative poly-condensation reaction (op). both sal-2,5-clan and pdcbap were characterized by solubility tests, ft-ir, 1h-nmr spectroscopy and tg-dta studies. ft-ir and 1h-nmr...

Phytochemical studies on Galanthus elwesii resulted in the isolation of five alkaloids: incartine, hordenine, hippeastrine, 8-O-demethylhomolycorine and lycorine. The NMR data given previously for incartine were revised and completed by two-dimensional 1H-1H and 1H-13C chemical shift correlation experiments. In vitro studies on the bioactivity of incartine were carried out.

1H-1H and 31P-1H nuclear Overhauser effects and 31P NMR spin-lattice relaxation times were measured for a synthetic DNA poly(dA-dT).poly(dA-dT) in a low-salt aqueous solution. The results have shown that all bases in the double helix are anti-orientated with respect to deoxyribose residues and that the sugar-phosphate backbone has an alternating architecture.

An efficient synthesis of vinylphosphonates is described. This involves the reaction of alkyl cyanoformates and dialkyl acetylendicarboxylates in the presence of trialkyl phosphites. The 1H, 13C NMR, and 31P NMR spectra of vinylphosphonates having different substitution are consistent with the presence of two geometrical isomers.

NMR metabolic fingerprinting methods almost exclusively rely upon the use of one-dimensional (1D) 1H NMR data to gain insights into chemical differences between two or more experimental classes. While 1D 1H NMR spectroscopy is a powerful, highly informative technique that can rapidly and nondestructively report details of complex metabolite mixtures, it suffers from significant signal overlap t...

195pt and 1h nmr has been used to show that addition of chlorine and bromine to [pt(cn)4]2_ in presence of perchloric acid in water results in cyanide and water scrambling with formation of eleven complexes of the type [pt(cn)4-ncl(h2o)n+1](n-1)+ (n=0, 1, 2, 3, 4). addition of nbu4oh to this solution gives (nbu4)2[pt(cn)4cl(oh)]. nmr measurements in acetone also show cyanide and hydroxyl group ...