Quercitol, Inositol

Ph3rtin.—In the latter it is present in combination as a substance known as phytin. This substance is a calcium or magnesium salt of a hexa-phosphoric acid ester of inositol. It is the compound in which most of the phosphorus present in seeds is contained. 

Strictly speaking the terpenes are hydrocarbons which are present in, or are obtained by steam distillation from, certain natural products, such as camphor and oil of turpentine certain of the so-called essential or ethereal oils, mostly from conifer or citrus plants, e.g., oil of lemon various plant resins, and India rubber or caoutchouc. They are the mother substances of the individual constituents of the products just mentioned. In general usage the name terpenes includes not only the hydrocarbons but the various derivatives referred to above. 

Terpenes and Hemi-terpenes.—The more common lerpene hydrocarbons or terpenes in the narrow sense, such as those obtained from oil of turpentine and lemon oil, have the composition represented by the formula CjoHie. This is considered as the lerpene unit and certain members of the series which have the composition CsHs are termed hemi-terpenes. 

Olefine and Cyclic Terpenes.—Two distinct groups are known which have entirely different structure. The first and smaller group includes strictly aliphatic hydrocarbons belonging to the olefine or ethylene unsaturated series. The second group, which is much larger, includes cyclo-aliphatic hydrocarbons or as we have previously described them the hydro-aromatic hydrocarbons. Thus we have  

The simpler group in constitution is that of the olefine terpenes. This group is represented by terpenes obtained from the ethereal oils of lemon, orange, rose, geranium, etc., and from india rubber or caoutchouc. 

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The deoxyinositols (quercitols, cyclohexanepentols) are useful model compounds which display many of the physical and chemical properties of true deoxy sugars. Although (-b)-proto-quercitol, the best known isomer, was isolated from nature 118 years ago, no synthesis has been reported up until now. The synthesis here described is actually that of the (-)-enantiomer, starting with (-)-inositol however, identical procedures applied to the readily available ( + ) or dl-inositol would give (- -) or DL-proto-quercitol, respectively. The natural occurence of, )-proto-quercitol has... 

The vibo or dl (124/35) quercitol (4) needed for the synthesis was prepared from rat/o-inositol (2) via the bromoquercitol (3) according to the method of McCasland and Horswill, (28). By acetonation, acetylation, deacetonation, and equatorial mesylation the mesyloxy derivative... 

It was not until 1966 that the synthesis of proto-quercitol (levo) was finally accomplished (30) by indirect removal of the position 2 hydroxyl group in (—) -inositol (14). 

The identical synthetic procedures applied to ( + )-inositol or dl-inositol should lead to ( + )-proto-quercitol and DL-proto-quercitol, respectively. Since the total synthesis of DL-inositol had previously been reported (33), the new syntheses of the various forms of proto-quercitol are total, with the possible exception of the step for resolution of DL-inositol, which so far has been accomplished only by a microbiological method (43). 

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. 

The present review is to be regarded as a continuation of Fletcher s article1 the facts described therein will not be repeated here unless required for the understanding of recent developments. Because of the considerable expansion of cyclitol chemistry, it is not practicable to cover, as Fletcher did, all compounds of the cyclitol group. Only the inositols, the quercitols, and the inosamines, their derivatives, and some closely related compounds will be discussed the tetrahydroxycyclo-hexanes and -hexenes, and quinic and shikimic acids—on which subjects many important papers have appeared—are not reviewed here.3... 

According to the Angyal proposals, the cyclohexanepenfo/s are all called quercitols, and these compounds, like the pentahydroxycyclohexanones inososes), are differentiated by trivial prefixes, the same prefix being used for the quercitol and the inosose of the same configuration. These prefixes are shown under the formulas CXXXIX-CXLIV (see p. 190). In the Fletcher-Anderson-Lardy system, these compounds are named as deoxy and keto derivatives, respectively, of inositols. The Angyal names will be... 

Tetrahydroxybenzoquinone can also be hydrogenated at high pressure and temperature with a Raney nickel catalyst,18 to give products ranging from cyclohexanediols to inositols. The yield of myo-inositol is small (2-6 %) somewhat larger proportions of cfs-inositol and czs-quercitol are produced. 

Some choice between the two possible mechanisms can be made by studying the periodate oxidation of pinitol,66 sequoyitol,78 and profo-quercitol.79 If a methylene (deoxy) or an O-methyl group should occur at C3 or C4 of the hexodialdose, the rapid periodate oxidation of the cyclic form XXXVI would end after the consumption of only 2 or 3 moles of periodate per mole, respectively, and would then continue only at the very slow rate governed by the hydrolysis of the formate ester. The above compounds give hexo-dialdoses of this nature, but they rapidly consume some four moles of periodate per mole. This indicates that the major path of the reaction is not the one by way of cyclic intermediates this conclusion is probably valid for the inositols, too. 

From the change of pH caused by successive additions of cyclitols to a borate solution, the equilibrium constants of complex formation have been calculated66 they show that the complexes are formed from cyclitol and borate in a 1 1 ratio. The stability of the tridentate borates depends on the steric disposition of the free hydroxyl groups in the complex the more of these in axial positions, the less stable the complex. This is illustrated by the values of the equilibrium constant in the following two series which are arranged by decreasing number of free axial hydroxyl groups in the complex scyWo-quercitol, 5.0 epf-quercitol, 310 m-quercitol, 7900 myoinositol, 25 epi-inositol, 700 and m-inositol, 1.1 X 106. When the constitution of a cyclitol allows the formation of both the tridentate and the classical, cis-1,2 type of complex, the former predominates. 

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]

In addition to those previously reported,1 Posternak239 has prepared a number of compounds related to C -methyl-inositols, such as methylene-sc /Z/o-quercitol (CXXXII), sq/ZZo-inositolcarboxylic acid (CXXXV), and m7/o-inositol-2-carboxylic acid (CXXXIV). These were synthesized from the epoxide CXXX as shown above. 

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. 

Tables II to X give the melting points and, where applicable, the optical rotations of the inositols, inososes, inosamines, and quercitols, and of all of their known O-substituted derivatives. Anhydroinositols, although not substitution products in the strict sense, are included, as are the carbonyl-functional derivatives of the inososes. Halogen- and nitro-substituted cyclitols, and the C-methyl-inositols and their derivatives, are not included most of these compounds are referred to in the text. The derivatives are arranged in the following order salts (inosamines) or functional derivatives (inososes), carboxylic esters, borates, nitrates, sulfonic esters, phosphates, glycosides, acetals (and Schiff bases), ethers (and IV-alkyl derivatives), and anhydrides.

Inositol is formed from D-glucose 6-phosphate by direct cyclization of the chain. D-Glucose 6-phosphate was also shown to be a precursor of deoxyinositols in leaf tissues, as D-glucose-6-t 6-phosphate (72) was converted193 into quercitol-2-t (l-2,3,5/1,4) (73) and194 viburnitol-4-t (l-1,2,4/3,5) (74). Labeling in the precursor and the products corresponded to a direct cyclization-mechanism. 

Quercitol (= Acorn sugar 2-Deoxy-D-chiro-inositol) (cyclitol) Quercus robur (oak) (Fagaceae) [acorn], Chamaerops humilis (Palmae) [leaf], Mimusops elengii (Sapotaceae) Sweet... 

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. 

Posternak employed permanganate oxidation of quercitol and obtained the conclusive derivative, metasaccharinic acid, which from data already published, he showed to have the configuration XLVIII. From this it may be seen that formula XLIV represents dea [Pg.67]

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. 

Jansen in 1913 and Ackermann in 1921 independently reported the discovery of a polyalcohol in the edible mussel, Mytilus edulis. This substance was named mytilitol and was considered by its first discoverer to be an isomer of quercitol and by its second discoverer to be a C-methyl inositol. Daniel and Doran several years later reviewed the evidence, which they considered to favor Ackermann s interpretation. 

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). ... 

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