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 matter, organic materials, i.e., matter in its various forms that contain ...

, a cyclitol is a

cycloalkane In organic chemistry, the cycloalkanes (also called naphthenes, but distinct from naphthalene) are the ring (chemistry), monocyclic Saturated and unsaturated compounds, saturated hydrocarbons. In other words, a cycloalkane consists only of hydroge ...

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 hydroxy ...

, 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 any substituent or moiety (chemistry), moiety in a molecule that causes the molecule's characteristic chemical reactions. The same functional group will undergo the same or similar chemical reactions r ...

s for the

hydrogen Hydrogen is a chemical element; it has chemical symbol, symbol H and atomic number 1. It is the lightest and abundance of the chemical elements, most abundant chemical element in the universe, constituting about 75% of all baryon, normal matter ...

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 Osmoprotectants or compatible solutes are small organic molecules with neutral charge and low toxicity at high concentrations that act as osmolytes and help organisms to survive in extreme osmotic stress. Osmoprotectants can be placed in three che ...

which are formed in a plant as a response to salt or water stress. Some cyclitols (e.g. quinic or

shikimic acid Shikimic acid, more commonly known as its anionic form shikimate, is a cyclohexene, a cyclitol and a cyclohexanecarboxylic acid. It is an important biochemical metabolite in plants and microorganisms. Its name comes from the Japanese flower ''shik ...

) are parts of

hydrolysable tannin A hydrolysable tannin or pyrogallol-type tannin is a type of tannin that, on heating with hydrochloric or sulfuric acids, yields gallic or ellagic acids. At the center of a hydrolysable tannin molecule, there is a carbohydrate (usually D-gluco ...

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 a compound that contains the same number and type of atoms, but with a different connectivity (i.e. arrangement of bonds) between them. The ...

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 in ...

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 In biochemistry, medicine, and related sciences, inositol generally refers to ''myo''-inositol (formerly ''meso''-inositol), the most important stereoisomer of the chemical compound cyclohexane-1,2,3,4,5,6-hexol. Its elemental formula, formula is ...

), and two of them are

enantiomer In chemistry, an enantiomer (Help:IPA/English, /ɪˈnænti.əmər, ɛ-, -oʊ-/ Help:Pronunciation respelling key, ''ih-NAN-tee-ə-mər''), also known as an optical isomer, antipode, or optical antipode, is one of a pair of molecular entities whi ...

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 In biochemistry, medicine, and related sciences, inositol generally refers to ''myo''-inositol (formerly ''meso''-inositol), the most important stereoisomer of the chemical compound cyclohexane-1,2,3,4,5,6-hexol. Its elemental formula, formula is ...

, 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 la ...

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

Ononitol The chemical compound ononitol is a derivative of inositol, specifically 4-O-methyl-''myo''-inositol: an ether that can be described as the result of replacing the hydroxyl (–OH) in position 4 of ''myo''-inositol by a methoxy group. This ...

; (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 the ...

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

Quebrachitol Quebrachitol is a naturally occurring optically active cyclitol, a cyclic polyol. It can be found in '' Allophylus edulis'' and in the serum left after the coagulation of the ''Hevea brasiliensis'' latex in the operation of rubber tapping. It is a ...

; (1R,2S,4S,5R)-6-methoxycyclohexane-1,2,3,4,5-pentol; 2-0-methyl-''chiro''-inositol *

Quinic acid Quinic acid is an organic compound with the formula . The compound is classified as 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 p ...

; (1S,3R,4S,5R)-1,3,4,5-tetrahydroxycyclohexanecarboxylic acid *

Shikimic acid Shikimic acid, more commonly known as its anionic form shikimate, is a cyclohexene, a cyclitol and a cyclohexanecarboxylic acid. It is an important biochemical metabolite in plants and microorganisms. Its name comes from the Japanese flower ''shik ...

; (3R,4S,5R)-3,4,5-trihydroxycyclohex-1-ene-1-carboxylic acid *

Valienol Valienol (streptol) is a C-7 cyclitol In organic chemistry, a cyclitol is a cycloalkane 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 ...

; (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 The lentil (''Vicia lens'' or ''Lens culinaris'') is an annual plant, annual legume grown for its Lens (geometry), lens-shaped edible ...

, a pinitol digalactoside

Phosphates

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

; (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 colored chemicals or substances. It can also be used for colorless chemicals that can be located by a stain or other visualisation method after separation. It is now primarily used as ...

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