Methyl /-glycosides members

The use of penodic acid oxidation m structure determination can be illustrated by a case m which a previously unknown methyl glycoside was obtained by the reaction of D arabmose with methanol and hydrogen chlonde The size of the nng was identified as five membered because only one mole of penodic acid was consumed per mole of glycoside and no formic acid was produced Were fhe nng six membered fwo moles of penodic acid would be required per mole of glycoside and one mole of formic acid would be produced... 

S-Deoxy Sugars.— Two members of the 2-deoxyaldohexose series have recently been found in small amounts. Somewhat more widely distributed are the two known 2,6-dideoxyhexoses (34) and (35), and still more frequent are their 3-methyl ethers. Members of the four theoretical pairs of this series are known, and those of the arabiuo, lyxo, and ribo configurations are found in glycosides in both enantiomorphs. D-Oleandrose has, however, been found only in lanafolein, which is not a cardenolide. It is remarkable that both diginoses occur in the Strophanthus species—the... 

Havonoids are made up of a number of classes of very similar groups in which two phenyl rings are connected by a three-carbon unit [10], The open structure members are yellow in color and termed as chalcones, and simple cyclization to a furanoid structure deepens the color to the orange aurones. The most usual flavonoids are, however, the pale-yellow flavones and flavonols, or 3-hydroxyflavones, which will be treated here, and the red-blue anthocyanins, which will be treated in the next section. Figure 13.4 shows examples of these main classes and their structural relationships. The natural compounds of all classes often occur as glycosides and as methyl ethers. 

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