Nuclear magnetic resonance dilution shift of the hydroxylic proton in the acetic acid-pyridine binary system

1987 ◽  
Vol 91 (25) ◽  
pp. 6440-6442 ◽  
Author(s):  
Tsuneo. Ikenoue ◽  
Nobuyuki. Yoshida

1965 ◽  
Vol 43 (8) ◽  
pp. 2306-2311
Author(s):  
Peter Yates ◽  
Thomas R. Lynch

The product from the action of methylmagnesium iodide on bicyclo[2.2.1]heptane-2,5-dione gave 2-exo-5-endo-diacetoxy-1,4-dimethylbicyclo[2.2.1]heptane on treatment with sulfuric acid in acetic acid. This has been converted to 1,4-dimethylbicyclo[2.2.1]heptane-2-exo-5-endo-diol, to 1,4-dimethylbicyclo[2.2.1]heptane-2,5-dione, and to 1,4-dimethylbicyclo[2.2.1]heptane-2-endo-5-endo-diol. The stereochemical assignments have been made on the basis of the interpretation of the nuclear magnetic resonance spectra of these compounds. The exo–endo diacetoxy compound is shown to be the expected product from a double Wagner–Meerwein rearrangement.





1963 ◽  
Vol 41 (10) ◽  
pp. 2417-2423 ◽  
Author(s):  
P. A. J. Gorin

The action on D-quinic acid of hot 95% acetic acid containing mineral acid gave, after complete acetylation, 1,4,5-tri-O-acetyl-epi-quinide consisting of approximately equal portions of the (−)- and (±)-isomers, and tetra-O-acetyl-scyllo-quinic acid. The stereochemistry of the products and their derived free polyols were determined by nuclear magnetic resonance (n.m.r.) spectroscopy and synthesis.Elimination of the tosyloxy group in 5-tosyl-epi-quinicol was shown to take place readily in aqueous acetic acid with participation of the primary carbinol group to give an anhydro quinicol derivative and epi-quinicol.



1989 ◽  
Vol 67 (2-3) ◽  
pp. 78-85 ◽  
Author(s):  
José L. Di Fabio ◽  
Jean-Robert Brisson ◽  
Malcolm B. Perry

Salmonella madelia reported to express the O-antigenic factors 1, 6, 14, and 25, defined in the Kauffmann–White classification system, was found to produce three different homogeneous lipopolysaccharides, which differed in having three structurally distinct O-polysaccharide components. The O-polysaccharide fraction obtained by mild acetic acid hydrolysis of the S. madelia lipopolysaccharide was analyzed by chemical composition, nitrous acid deamination, periodate oxidation, methylation, and 1H and 13C nuclear magnetic resonance methods and was demonstrated to be composed of three polysaccharides, PS(I), PS(II), and PS(III), which had the structures of repeating oligosaccharide units:[Formula: see text]Key words: Salmonella madelia, lipopolysaccharide, structure, analysis, nuclear magnetic resonance.



Sign in / Sign up

Export Citation Format

Share Document