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M Stacey

Publications and source records attributed to M Stacey.

At least 73 records · Page 4Linked to original sources
PubMed1977

Structural identification of isomeric O-trimethylsilyl derivatives of some hexuronic acids.

The structures of the isomeric products obtained on trimethylsilylation of naturally occurring hexuronic acids and their sodium salts and lactones have been established by the application of n.m.r. (for anomeric configuration) and mass spectrometry (for ring size). The equilibria of some of the hexuronic acids in methyl sulphoxide involved a larger proportion of furanoid forms than those in water or pyridine. The proportion of furanoses was also increased by the addition of hexamethyldisilazane. Kinetic evidence indicated that two molecules of each hexuronic acid interacted autocatalytically during mutarotation.

Hexuronic Acids↗
PubMed1976

G.L.C. of the O-trimethylsilyl derivatives of hexuronic acids.

The free acids, sodium salts, and lactones of several hexuronic acids have been studied as their O-trimethylsilyl derivatives by gas-liquid chromatography using SE-30 and XE-60 liquid phases. Silylation was best performed in methyl sulphoxide. The equilibrium between the various forms of a hexuronic acid in methyl sulphoxide was also studied by g.l.c. following silylation. The hexamethyldisilazane used in the silylation disturbed the equilibrium attained in the solvent, but this was overcome by premixing the hexamethyldisilazane with chlorotrimethylsilane. Methyl sulphoxide and the silylating reagents gave a two-phase system in which the derivative was favourably partitioned into the upper layer. Partition coefficients and stabilities of the derivatives were measured, and a g.l.c. method for the analysis of the hexuronic acids was thereby developed. The oximes of the hexuronic acids were studied as alternative derivatives for g.l.c., and their equilibrium compositions and g.l.c. retention times are recorded.

Chromatography, Gas↗