In organic chemistry, 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 containing ...

containing at least three hydroxyl, 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 groups for the hydrogen atoms in such a molecule, as well as similar molecules with one or more double bonds 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 chemical compound, compound is another compound whose molecule has the same number of atoms of each element, but with logically distinct chemical bond, b ...

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 stereoisomers, 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 Inositol, or more precisely ''myo''-inositol, is a carbocyclic sugar that is abundant in the brain and other mammalian tissues; it mediates cell signal transduction in response to a variety of hormones, neurotransmitters, and growth factors and ...

), 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 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 Inositol, or more precisely ''myo''-inositol, is a carbocyclic sugar that is abundant in the brain and other mammalian tissues; it mediates cell signal transduction in response to a variety of hormones, neurotransmitters, and growth factors and ...

, or cyclohexane-1,2,3,4,5,6-hexol; four out of nine possible isomers. *

Cyclohexanetetrol A cyclohexanetetrol is a chemical compound consisting of a cyclohexane molecule with four hydroxyl groups (–OH) replacing four of the twelve hydrogen atoms. It is therefore a cyclitol (cyclic polyol). Its generic formula is or . Some cyclohexane ...

J. 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 Pinitol is a cyclitol, a cyclic polyol. It is a known anti-diabetic agent isolated from ''Sutherlandia frutescens'' leaves. Gall plant tannins can be differentiated by their content of pinitol. It was first identified in the sugar pine (''Pinus lam ...

; (1S,2S,4S,5R)-6-methoxycyclohexane-1,2,3,4,5-pentol; 3-O-methyl-D-''chiro''-inositol *

Ononitol Ononitol is a cyclitol. It is a 4-''O''-methyl-myo-inositol and is a constituent of ''Medicago sativa Alfalfa () (''Medicago sativa''), also called lucerne, is a perennial flowering plant in the legume family Fabaceae. It is cultivated as an ...

; (1R,2S,3S,4S,5S,6S)-6-methoxycyclohexane-1,2,3,4,5-pentaol; 4-O-methyl-''myo''-inositol *

Pinpollitol Pinpollitol is a cyclitol. It is a di-''O''-methyl-(+)- chiro-inositol that can be isolated from ''Pinus radiata ''Pinus radiata'' ( syn. ''Pinus insignis''), the Monterey pine, insignis pine or radiata pine, is a species of pine native to th ...

; (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 ...

; (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 Valienol (streptol) is a C-7 cyclitol similar in structure to valienamine Valienamine is a C-7 aminocyclitol found as a substructure of pseudooligosaccharides such as the antidiabetic drug acarbose and the antibiotic validamycin. It can be fo ...

; (1S,2S,3S,4R)-5-(Hydroxymethyl)cyclohex-5-ene-1,2,3,4-tetrol *

Viscumitol Viscumitol is a cyclitol. It is a dimethyl-ether of ''muco''-inositol that can be isolated from ''Viscum album ''Viscum album'' is a species of mistletoe in the family Santalaceae, commonly known as European mistletoe, common mistletoe or sim ...

(1R,2S,3R,4S,5R,6S)-5,6-dimethoxycyclohexane-1,2,3,4-tetraol; 1,2-di-O-methyl-''muco''-inositol

Glycosides

Ciceritol Ciceritol is a cyclitol. It is a pinitol digalactoside that can be isolated from seeds of chickpea, lentil and white lupin ''Lupinus albus'', commonly known as the white lupin or field lupine, is a member of the genus ''Lupinus'' in the famil ...

, a pinitol digalactoside

Phosphates

Phytic acid Phytic acid is a six-fold dihydrogenphosphate ester of inositol (specifically, of the ''myo'' isomer), also called inositol hexakisphosphate (IP6) or inositol polyphosphate. At physiological pH, the phosphates are partially ionized, resulting ...

; (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 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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