Other Quercitols

Power and Tutin in 1904 reported the discovery of a polyhydric alcohol in the leaves of Gymnema sylvestre Br., one of the Asclepiadaceae. Elementary analysis of the compound and of its esters, as well as oxidation with permanganate to malonic acid, demonstrated the close relationship of the material to dexiro-quercitol. However, this latter compound rotates -f 24° while the compound of Power and Tutin rotated — 73.9° (for the hydrate) and so this levorotatory quercitol is not the enantiomorph of dexiro-quercitol. As yet no information concerning its configuration has been published. 

An interesting transition from the inositol to the quercitol series has recently been accomplished by Posternak. While hydrogenation of scyllo-meso-inosose with platinum oxide as a catalyst in neutral solution gave the expected mixture of meso-inositol and scyllitol, it was found that, when the reduction was carried out in dilute sulfuric acid solution, two moles of hydrogen rather than one were consumed and the product was a desoxyinositol, presumably the symmetrical form XLIX. That this reaction does not proceed through an inositol is shown by the stability of mcso-inositol under the conditions of the experiment. 

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Other quercitols have been synthesized by catalytic hydrogenolysis of the corresponding inososes (see p. 180). All the known quercitols are shown, with their names, in formulas CXXXIX-CXLIV according to Angyal and Macdonald s proposals,6 the quercitol of acorn is called (+)-profo-quercitol, and natural viburnitol is named (—)-w 6o-quercitol the corresponding Fletcher-Anderson-Lardy names are (+)-1 -deoxy-mwco-inositol and ( —)-1-deoxy-WM/o-inositol. Synthesis of the four as-yet-unknown diastereomers should not present serious difficulties. 

The quercitols (cyclohexanepentols) are less important than the inositols. All the stereoisomers predicted by theory are now known but only two of them were found in Nature (-i-)- 0to-quercitol (IX) originally named querdtol , in the acom and several other sources, and (—)-vi6o-quercitol (X) first named /evo-rotatory querdtol and later vibnmitol . in several plants. Other quercitols have been made by catal3dic hydrogenation of inososes in acid solution. 

The Synthesis of (— -proto-Quercitol, Although proto-quercitol (dextro) was discovered in 1849 ( 5), its cyclohexanepentol structure was not established until 1885 (13), and its configuration not until 1932. (38). The synthesis of this well-known cyclitol has been a difficult problem, since it appears that nearly every synthetic reaction commonly employed for other cyclitols would lead stereospecifically to the wrong product. 

Of all the polyhydroxy compounds studied in aqueous solution,63 os-inositol exhibits the greatest mobility. The ept- and aUo-inositol and o s-quercitol also Bhow considerable movement, but to a lower degree other cyclitols are Iobs mobile. Reducing sugars and alditols generally show very little or no movement in the presence of Mg29 and alkali metal ions all move in the presence of Ca , Sr , and Ba1 , but the rates are only moderate. Table III gives the relative mobilities of several polyhydroxy compounds in aqueous solutions of various metal ions. 

CHOH.(CHOH)2.CH2, (CHOH)2 mw 164.16 monoclinic crysts with a sweet taste mp 234— 35° sol in w si sol in hot, almost insol in cold ale practically insol in eth. Found in the acoms of various species of Quercus Fagaceae (Refs 2, 3 6). Its structure was detd by Kiliani (Ref 7), Postemak (Ref 8), and others (Ref 1, p [1151]). On nitration, it forms an expl compd Quercitol Pentenitrate (Nitroquercite). C6H7(0N02)s, mw 389.16, N 18.00%, OB to CO —2.1% nearly colorl, transparent, resinous substance mp, explds... 

Recently, it has been reported101 that mt/o-inositol reacts rapidly and stoichiometrically with periodate at 50-65°. If the excess periodate is determined spectrophotometrically,102 a sensitive and convenient micromethod results (range 2-70 jug.). That this method will become the one of choice for m/o-inositol seems probable. It should be applicable to the other inositols, and, perhaps, with some modifications, to inositol methyl ethers, quercitols, etc. Most interfering substances are effectively removed by vigorous treatment with hot, concentrated hydrochloric acid,101(a) sulfuric acid,103 or barium hydroxide,101[Pg.158]

Carlavilla, D., Villamiel, M., Martfnez-Castro, I., Moreno-Arribas, M.V. (2006). Occurrence and significance of quercitol and other inositols in wine during oak wood aging. Am. J. Enol. Vitic., 57, 468-473. 

Similarly, a convenient synthesis of (y )-1alo- and ( )-vzho-quercitol and other inositol derivatives has been accomplished, by adopting the addition of singlet oxygen onto a suitable cyclohexene precursor as the key photochemical step (Scheme 2.26). ... 

As yet, only the (+)-proproto-quercitol (IS) is present in all of 33 species of the genus Quercus examined, and it seems to be present in every part of the tree. Nineteen plant species from eight other botanical families also contain profo-querci-tol. ... 

Levorotatory yf6o-quercitol (30) is present in Viburnum tinus L. and in at least three other botanical genera. ... 

In this Section, synthetic methods and configurational evidence for the ten quercitols (listed alphabetically) are briefly described. Simple derivatives (other than acetates, see Table I) are mentioned. The 6-substituted quercitols, and the nuclear magnetic resonance or optical rotatory configurational proofs, are described in later Sections. 

The 1-phosphate ester of this diol is said to occur in brain tissue and sea-urchin eggs. Strong evidence that cordycepic acid is really D-mannitol. Not an enantiomorph of d-quercitol other isomeric relationship is involved. 

Tannins involving (—)-shikimic acid (12), quinic acid (13), 5cy//o-quercitol (14), and proto-quercitol (15) (Fig. 12.1) cores are known. Most of the unusual types that have been studied are from the genus Quercus (oaks) and other members of the family Fagaceae (Porter, 1989). 

D-Quercitol (73) is common in members of the genus Quercus, oaks, of the family Fagaceae. This cyclitol derivative is known from at least nine other families. D-Pinitol (63) is known from six families of gymnosperms, in which it is widespread, but it is also known from a number of angio-sperms. 

Yeast growth has been used as an assay-method for inositol (358, 431, 443). Woolley (443) examined the specificity of inositol by the yeast growth response (Hansen No. 1 strain of Toronto yeast) and for the curative effect on mice with an alopecia due to inositol deficiency (Table XXVII). The results were of the same type as with other growth factors apparently those compoimds are active w hich can readily form inositol, and any marked departure from this results in inactivity, e.g., quercitol, inosose, and quinic acid. Although the mytilitol was a natural product it was concluded by Woolley that its activity could not be ascribed to contaminating inositol. 

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