organic chemistry Organic chemistry is a subdiscipline within chemistry involving the science, scientific study of the structure, properties, and reactions of organic compounds and organic materials, i.e., matter in its various forms that contain carbon atoms.Clay ...

, a cyclitol is a

cycloalkane In organic chemistry, the cycloalkanes (also called naphthenes, but distinct from naphthalene) are the monocyclic saturated hydrocarbons. In other words, a cycloalkane consists only of hydrogen and carbon atoms arranged in a structure containin ...

containing at least three

hydroxyl In chemistry, a hydroxy or hydroxyl group is a functional group with the chemical formula and composed of one oxygen atom covalently bonded to one hydrogen atom. In organic chemistry, alcohols and carboxylic acids contain one or more hydrox ...

, each attached to a different ring carbon atom. The general formula for an unsubstituted cyclitol is or where 3 ≤ ''x'' ≤ ''n''. The name is also used for compounds that can be viewed as result of substituting various

functional group In organic chemistry, a functional group is a substituent or moiety in a molecule that causes the molecule's characteristic chemical reactions. The same functional group will undergo the same or similar chemical reactions regardless of the res ...

s for the

hydrogen Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic ...

atoms in such a molecule, as well as similar molecules with one or more

double bond In chemistry, a double bond is a covalent bond between two atoms involving four bonding electrons as opposed to two in a single bond. Double bonds occur most commonly between two carbon atoms, for example in alkenes. Many double bonds exist betw ...

s in the ring. Cyclitols and their derivatives are some of the compatible solutes which are formed in a plant as a response to salt or water stress. Some cyclitols (e.g. quinic or shikimic acid) are parts of hydrolysable tannins.

Isomerism and nomenclature

Unsubstituted cyclitols with the same ring size and number of hydroxyls may exist in several

structural isomer In chemistry, a structural isomer (or constitutional isomer in the IUPAC nomenclature) of a compound is another compound whose molecule has the same number of atoms of each element, but with logically distinct bonds between them. The term met ...

s, depending on the position of the hydroxyls along the ring. For example, cyclohexanetriol exists in three distinct isomers (1,2,3-, 1,2,4-, and 1,3,5-). Furthermore, the hydrogen and the hydroxyl on each carbon atom may lie in two possible arrangements relative to the local ring plane; so that each structural isomer may exist in several

stereoisomer In stereochemistry, stereoisomerism, or spatial isomerism, is a form of isomerism in which molecules have the same molecular formula and sequence of bonded atoms (constitution), but differ in the three-dimensional orientations of their atoms i ...

s, depending on which side of the ring plane the hydroxyls are. For example, there are nine stereoisomers of 1,2,3,4,5,6-cyclohexanehexol ( inositol), and two of them are

enantiomer In chemistry, an enantiomer ( /ɪˈnænti.əmər, ɛ-, -oʊ-/ ''ih-NAN-tee-ə-mər''; from Ancient Greek ἐνάντιος ''(enántios)'' 'opposite', and μέρος ''(méros)'' 'part') – also called optical isomer, antipode, or optical ant ...

s. The

IUPAC The International Union of Pure and Applied Chemistry (IUPAC ) is an international federation of National Adhering Organizations working for the advancement of the chemical sciences, especially by developing nomenclature and terminology. It is ...

has provided a nomenclature for cyclitol stereoisomers.CON and CBN IUPAC Commissions on Nomenclature (1968): "The Nomenclature of Cyclitols - Tentative Rules". ''European Journal of Biochemistry'', volume 5, pages 1-12.

Naturally occurring cyclitols

Unsubstituted

Conduritol Conduritol or 1,2,3,4-cyclohexenetetrol is any of the organic compounds with chemical formula C6H10O4, that can be seen as derivatives of cyclohexene with four hydroxyl groups (OH) replacing hydrogen atoms on the four carbon atoms not adjacent to t ...

, or cyclohex-5-ene-1,2,3,4-tetrol; two out of ten possible isomers. * Inositol, or cyclohexane-1,2,3,4,5,6-hexol; four out of nine possible isomers. * CyclohexanetetrolJ. S. Craigie (1969): "Some Salinity-Induced Changes in Growth, Pigments, and Cyclohexanetetrol Content of ''Monochrysis lutheri''". ''Journal of the Fisheries Research Board of Canada'', volume 26, issue 11, pages 2959-2967.

Substituted

* Bornesitol; (1R,2R,3S,4S,5R,6S)-6-methoxycyclohexane-1,2,3,4,5-pentol; D-(−)-O-methyl-''myo''-inositol * Pinitol; (1S,2S,4S,5R)-6-methoxycyclohexane-1,2,3,4,5-pentol; 3-O-methyl-D-''chiro''-inositol * Ononitol; (1R,2S,3S,4S,5S,6S)-6-methoxycyclohexane-1,2,3,4,5-pentaol; 4-O-methyl-''myo''-inositol * Pinpollitol; (1R,2R,3R,4S,5R,6S)-3,6-dimethoxycyclohexane-1,2,4,5-tetraol; di-O-methyl-(+)-''chiro''-inositol * Quebrachitol; (1R,2S,4S,5R)-6-methoxycyclohexane-1,2,3,4,5-pentol; 2-0-methyl-''chiro''-inositol *

Quinic acid Quinic acid is a cyclitol, a cyclic polyol, and a cyclohexanecarboxylic acid. It is a colorless solid that can be extracted from plant sources. Quinic acid is implicated in the perceived acidity of coffee. Occurrence and preparation The compound i ...

; (1S,3R,4S,5R)-1,3,4,5-tetrahydroxycyclohexanecarboxylic acid * Shikimic acid; (3R,4S,5R)-3,4,5-trihydroxycyclohex-1-ene-1-carboxylic acid * Valienol; (1S,2S,3S,4R)-5-(Hydroxymethyl)cyclohex-5-ene-1,2,3,4-tetrol * Viscumitol (1R,2S,3R,4S,5R,6S)-5,6-dimethoxycyclohexane-1,2,3,4-tetraol; 1,2-di-O-methyl-''muco''-inositol

Glycosides

* Ciceritol, a pinitol digalactoside

Phosphates

* Phytic acid; (1R,2S,3r,4R,5S,6s)-cyclohexane-1,2,3,4,5,6-hexayl hexakis ihydrogen(phosphate) inositol hexakisphosphate

Other cyclitols

1,2,3,4-Cyclohexanetetrol 1,2,3,4-Cyclohexanetetrol (also named cyclohexane-1,2,3,4-tetrol, 1,2,3,4-tetrahydroxycyclohexane, or ''ortho''-cyclohexanetetrol) is an organic compound whose molecule can be described as a cyclohexane with four hydroxyl (OH) groups substituted fo ...

Nihat Akbulut and Metin Balci (1988): "A new and stereospecific synthesis of cyclitols: (1,2,4/3)-, (1,2/3,4)-, and (1,3/2,4)-cyclohexanetetrols". ''Journal of Organic Chemistry'', volume 53, issue 14, pages 3338-3342. *

1,2,3,4,5-Cyclopentanepentol 1,2,3,4,5-Cyclopentanepentol, also named cyclopentane-1,2,3,4,5-pentol or 1,2,3,4,5-pentahydroxycyclopentane is a chemical compound with formula or , whose molecule consists of a ring of five carbon atoms (a cyclopentane skeleton), each connected ...

Analysis methods

In 1955, Posternak and others described the separation of cyclitols by

paper chromatography Paper chromatography is an analytical method used to separate coloured chemicals or substances. It is now primarily used as a teaching tool, having been replaced in the laboratory by other chromatography methods such as thin-layer chromatograph ...

in various solvents, and three methods of development: Tollens reagents, the Meillère reagent (based on the Scherer-Gallois reaction), and digestion by ''

Acetobacter suboxydans ''Acetobacter'' is a genus of acetic acid bacteria. Acetic acid bacteria are characterized by the ability to convert ethanol to acetic acid in the presence of oxygen. Of these, the genus ''Acetobacter'' is distinguished by the ability to oxidiz ...

'' followed by Tollens reagent.Th. Posternak, D. Reymond, W. Haerdi (1955): "Recherches dans la série des cyclitols XX. Chromatographie sur papier de cyclitols et de cycloses". ''Helvetica Chimica Acta'' volume 38, issue 1, pages 191-194

References

External links

List of cyclitol molecules on chemicalland21.com
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