David W. Cochran

The structure of gelsevirine

Die Massenspektren und1H- und13C-NMR-Spektren der Gelsemium-Alkaloide Gelsemin, Gelsedin und Gelsevirin wurden aufgenommen und vollständig analysiert. Gelsevirin wurde durch Reduktion in Gelsemin übergeführt und besitzt die Struktur des Na-Methoxygelsemins.

2(S),4(R)-4-(β-d-Galactopyranosyloxy)-4-isobutyl-glutamic acid: A new amino acid in Reseda odorata

Abstract 2( S ),4( R )-4-(β- d -Galactopyranosyloxy)-4-isobutylglutamic acid (I) has been isolated from the flowers of Reseda odorata , wherein it occurs in substantial quantity. Hydrolysis of I gives d -galactose, 2( S ),4( R )-4-hydroxy-4-isobutylglutamic acid (II) and 3( R ),5( S )-3-hydroxy-3-isobutyl-2-pyrrolidone-5-carboxylic acid (III) and its treatment with nitrous acid yields a galactoside of a non-nitrogenous hydroxy acid lactone (IV). The structures of I and its degradation products are supported by PMR, 13 C-NMR and other spectroscopic methods. 13 C-NMR spectroscopy of the model compound 2-(β- d -galactopyranosyloxy)isobutyric acid confirmed the structure of the natural product. The S - (or l -) configuration at C(2) in the amino acid moiety of I has been established by the use of the Clough—Lutz—Jirgenson rule and the R -configuration at C(4) of the same unit has been assigned tentatively. I represents the first example of a glycoside of a higher plant amino acid in which the carbohydrate residue is linked to an aliphatic hydroxy group.

Carbon-13 nuclear magnetic resonance spectroscopy of naturally occurring substances. Gelsemine

A 13C n.m.r. spectrum of the alkaloid gelsemine has been recorded and the signals of all carbons assigned.

13 C Nuclear magnetic resonance spectroscopy of naturally occurring substances. Camphor and related compounds

All 13C chemical shifts of camphor and other bicyclo[2,2,1]heptanones have been determined.