Cyclohexane-1,2,3,4,5,6-hexol

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Cyclohexane-1,2,3,4,5,6-hexol [1]
Cis-inositol.svg
cis-Inositol
Names
IUPAC name
cyclohexane-1,2,3,4,5,6-hexol
Systematic IUPAC name
Cyclohexane-1,2,3,4,5,6-hexol
Other names
Inositol
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
KEGG
PubChem CID
UNII
  • InChI=1S/C6H12O6/c7-1-2(8)4(10)6(12)5(11)3(1)9/h1-12H/t1-,2-,3-,4+,5-,6- Yes check.svgY
    Key: CDAISMWEOUEBRE-GPIVLXJGSA-N Yes check.svgY
  • InChI=1/C6H12O6/c7-1-2(8)4(10)6(12)5(11)3(1)9/h1-12H/t1-,2-,3-,4+,5-,6-
    Key: CDAISMWEOUEBRE-GPIVLXJGBG
  • O[C@@H]1[C@@H](O)[C@H](O)[C@H](O)[C@H](O)[C@H]1O
Properties
C6H12O6
Molar mass 180.16 g/mol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Cyclohexane-1,2,3,4,5,6-hexol is a family of chemical compounds with formula C6H12O6, whose molecule consists of a ring of six carbon atoms, each bound to one hydrogen atom and one hydroxyl group (–OH). There are nine stereoisomers, that differ by the position of the hydroxyl groups relative to the mean plane of the ring. All these compounds are sometimes called inositol, although this name (especially in biochemistry and related sciences) most often refers to a particular isomer, myo-inositol, which has many important physiological roles and medical uses.

Contents

These compounds are classified as sugars, specifically carbocyclic sugars or sugar alcohols, to distinguish them from the more common aldoses like glucose. They generally have sweet taste. [2]

These compounds form several esters with biochemical and industrial importance, such as phytic acid and phosphatidylinositol phosphate,

Isomers and structure

The nine stereoisomers of cyclohexane-1,2,3,4,5,6-hexol are distinguished by prefixes: myo-, scyllo-, muco-, D-chiro-, L-chiro-, neo-, allo-, epi-, and cis-inositol.

As their names indicate, L- and D-chiro inositol are chiral, a pair enantiomers (mirror-image forms). All the others are meso compounds (indistinguishable from their mirror images). [3]

Myo-inositol.svg Scyllo-inositol.svg Muco-inositol.svg
myo-scyllo-muco-
Neo-inositol.svg Allo-inositol.svg Epi-inositol.svg
neo-allo-epi-
Cis-inositol.svg
D-chiro-inositol.svg L-chiro-inositol.svg
cis-D-chiro-L-chiro-

Racemate

The designation rac-chiro-inositol has been used for the racemic mixture (racemate) of equal parts of the two chiro isomers. It crystallizes as a single phase, rather than separate D and L crystals, that melts at 250 °C (which is 4–5 °C higher than the melting point of the pure enantiomers) and decomposes between 308 and 344 °C. The crystal structure is monoclinic with the group. The crystal cell parameters are a = 1014.35 pm, b = 815.42 pm, c = 862.39 pm, β = 92.3556°, Z = 4. The cell volume is 0.71270 nm 3, or about 0.178 nm3 per molecule (which is a bit smaller than the typical volumes of other isomers). [4]

Ring conformation

As in cyclohexane, the C6 ring of these compounds can be in two conformations, "boat" and "chair". The relative stability of the two forms varies with the isomer, generally favoring the conformation where the hydroxyls are farthest apart from each other. [5]

Melting points

Some of the stereoisomers crystallize in more than one polymorph, with different densities and melting points — which range from 225 °C for myo-inositol to about 360 °C for polymorph "B" of scyllo-inositol. [4] There is a clear correlation between the melting points and the number and type of chains of hydrogen-bonded hydroxyls. [6]

Biochemistry

All isomers except allo- and cis- occur in nature, although myo-inositol is substantially more abundant and important than the others. [7] [8]

In humans, myo-inositol is synthesized mostly in the kidneys, from glucose 6-phosphate. [9] Small amounts of myo-inositol are then converted by a specific epimerase to D-chiro-inositol, [10] which is an important messenger molecule in insulin signaling. [11]

A 2020 study found detectable amounts of epi-, neo-, chiro-, scyllo-, and myo-inositol in the urine of women, pregnant or not. Concentrations of myo and scyllo increased significantly in the third trimester of pregnancy, with scyllo varying between 20% and 40% of myo. Concentrations of epi, neo, and chiro were always a few percent of those of myo, except that chiro- reached 20% of myo in the second trimester of pregnancy. [8]

The bacterium Bacillus subtilis can metabolize myo-, scyllo-, and D-chiro-inositol.and convert to and from these three isomers. [12]

Phytic acids

myo-Inositol hexakis-dihidrogenphosphate, or phytic acid Phytic acid.svg
myo-Inositol hexakis-dihidrogenphosphate, or phytic acid

Plants synthesize inositol hexakis-dihydrogenphosphate, also called phytic acid or IP6, as a storage of phosphorus [13] Inositol penta- (IP5), tetra- (IP4), and triphosphate (IP3) are also called "phytates"

Related Research Articles

In chemistry, a pentose is a monosaccharide with five carbon atoms. The chemical formula of many pentoses is C
5H
10O
5, and their molecular weight is 150.13 g/mol.

<span class="mw-page-title-main">Stereoisomerism</span> When molecules have the same atoms and bond structure but differ in 3D orientation

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 space. This contrasts with structural isomers, which share the same molecular formula, but the bond connections or their order differs. By definition, molecules that are stereoisomers of each other represent the same structural isomer.

<span class="mw-page-title-main">Hexose</span> 6-Carbon simple sugar

In chemistry, a hexose is a monosaccharide (simple sugar) with six carbon atoms. The chemical formula for all hexoses is C6H12O6, and their molecular weight is 180.156 g/mol.

<span class="mw-page-title-main">Inositol</span> Carbocyclic sugar

In biochemistry, medicine, and related sciences, inositol generally refers to myo-inositol, the most important stereoisomer of the chemical compound cyclohexane-1,2,3,4,5,6-hexol. Its formula is C6H12O6; the molecule has a ring of six carbon atoms, each with an hydrogen atom and a hydroxyl group (–OH). In myo-inositol, two of the hydroxyls, neither adjacent not opposite, lie above the respective hydrogens relative to the mean plane of the ring.

<span class="mw-page-title-main">Phosphatidylinositol</span> Signaling molecule

Phosphatidylinositol or inositol phospholipid is a biomolecule. It was initially called "inosite" when it was discovered by Léon Maquenne and Johann Joseph von Scherer in the late 19th century. It was discovered in bacteria but later also found in eukaryotes, and was found to be a signaling molecule.

<span class="mw-page-title-main">Phytic acid</span> Chemical compound

Phytic acid is a six-fold dihydrogenphosphate ester of inositol, also called inositol hexaphosphate, inositol hexakisphosphate (IP6) or inositol polyphosphate. At physiological pH, the phosphates are partially ionized, resulting in the phytate anion.

<span class="mw-page-title-main">Inositol oxygenase</span> Protein-coding gene in the species Homo sapiens

Inositol oxygenase, also commonly referred to as myo-inositol oxygenase (MIOX), is a non-heme di-iron enzyme that oxidizes myo-inositol to glucuronic acid. The enzyme employs a unique four-electron transfer at its Fe(II)/Fe(III) coordination sites and the reaction proceeds through the direct binding of myo-inositol followed by attack of the iron center by diatomic oxygen. This enzyme is part of the only known pathway for the catabolism of inositol in humans and is expressed primarily in the kidneys. Recent medical research regarding MIOX has focused on understanding its role in metabolic and kidney diseases such as diabetes, obesity and acute kidney injury. Industrially-focused engineering efforts are centered on improving MIOX activity in order to produce glucaric acid in heterologous hosts.

1<small>D</small>-<i>chiro</i>-Inositol Chemical compound

1D-chiro-Inositol or D-chiro-inositol is a chemical substance with formula C6H12O6, one of the nine isomers of cyclohexane-1,2,3,4,5,6-hexol. The molecule has a ring of six carbon atoms, each bound to one hydrogen atom and one hydroxyl (OH) group. The hydroxyls on atoms 1, 2, and 4, in counterclockwise order, lie above the plane of the ring. The molecule being distinct from its mirror image, the compound is chiral, hence its name. Its enantiomer is 1L-chiro-inositol.

<i>scyllo</i>-Inositol Chemical compound

scyllo-Inositol, also called scyllitol, cocositol, or quercinitol, is a chemical compound with formula C6H12O6, one of the nine inositols, the stereoisomers of cyclohexane-1,2,3,4,5,6-hexol. The molecule has a ring of six carbon atoms, each bound to one hydrogen atom and one hydroxyl group (–OH); if the ring is assumed horizontal, the hydroxyls lie alternatively above and below the respective hydrogens.

<span class="mw-page-title-main">Isomer</span> Chemical compounds with the same molecular formula but different atomic arrangements

In chemistry, isomers are molecules or polyatomic ions with identical molecular formula – that is, the same number of atoms of each element – but distinct arrangements of atoms in space. Isomerism refers to the existence or possibility of isomers.

<i>neo</i>-Inositol Chemical compound

The chemical compound neo-inositol is one of the nine stereoisomers cyclohexane-1,2,3,4,5,6-hexol, the "inositols". Its formula is C6H12O6; the six carbon atoms form a ring, each of them is bonded to a hydrogen atom and a hydroxyl group (–OH). If the ring is assumed horizontal, three consecutive hydroxyls lie above the respective hydrogens, and the other three lie below them.

<i>muco</i>-Inositol Chemical compound

muco-Inositol is a critically important chemical in the gustatory (taste) modality of the mammalian nervous system. The generic form is coupled to a phospholipid of the outer lemma of the sensory neurons associated with the sodium ion sensitive channel of gustation.

1<small>L</small>-<i>chiro</i>-Inositol Chemical compound

The chemical compound 1L-chiro-inositol is one of the nine stereoisomers of cyclohexane-1,2,3,4,5,6-hexol, with formula C6H12O6, the generic "inositol". Its molecule has a ring of six carbon atoms, each bonded to a hydrogen atom and a hydroxyl group (–OH). Imagining the ring is horizontal, the hydroxyls on carbons 1, 2, and 4, in clockwise order are above the respective hydrogens, while the other three are below them.

<i>epi</i>-Inositol Chemical compound

Epi-Inositol is one of the stereoisomers of inositol.

<i>cis</i>-Inositol Chemical compound

cis-Inositol is one of the isomers of inositol.

<i>allo</i>-Inositol Chemical compound

allo-Inositol is a stereoisomer of inositol.

<span class="mw-page-title-main">Cyclitol</span> Class of chemical compounds

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 C
nH
2n-x(OH)
x or C
nH
2nO
x where 3 ≤ x ≤ n.

<span class="mw-page-title-main">1,2,3,4,5-Cyclopentanepentol</span> Chemical compound

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 C
5H
10O
5 or (–CHOH–)
5, whose molecule consists of a ring of five carbon atoms, each connected to one hydrogen and one hydroxyl group. The unqualified term "cyclopentanepentol" usually refers to this compound. There are four distinct stereoisomers with this same structure.

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. Its generic formula is C
6H
12O
4 or C
6H
8(OH)
4.

<span class="mw-page-title-main">1,2,4,5-Cyclohexanetetrol</span> Chemical compound

1,2,4,5-Cyclohexanetetrol (also named cyclohexane-1,2,4,5-tetrol, 1,2,4,5-tetrahydroxycyclohexane, or para-cyclohexanetetrol) is an organic compound whose molecule can be described as a cyclohexane with four hydroxyl (OH) groups substituted for hydrogen atoms on two non-adjacent pairs of adjacent carbon atoms. Its formula can be written C
6H
12O
4, C
6H
8(OH)
4, or [–(CH(OH)–)2–CH
2–]2.

References

  1. ↑ Merck Index (11th ed.). p. 4883.
  2. ↑ G. G. Birch and M. G. Lindley (1973): "Cyclohexane polyols as sweet analogues of the sugars". Journal of Food Science, volume 38, issue 7, pages 1179-1181. doi : 10.1111/j.1365-2621.1973.tb07232.x
  3. ↑ Majumder, A. L.; Biswas, B. B. (2006-10-03). Biology of Inositols and Phosphoinositides. Springer Science & Business Media. ISBN   9780387276007.
  4. 1 2 Sándor L. Bekö, Edith Alig, Martin U. Schmidt, Jacco van de Streek (2014): "On the correlation between hydrogen bonding and melting points in the inositols". International Union of Crystallography Journal (IUCrJ), volume 1, part 1, pages 61-73. doi : 10.1107/S2052252513026511
  5. ↑ Brady, S.; Siegel, G.; Albers, R. W.; Price, D. (2005). Basic Neurochemistry: Molecular, Cellular and Medical Aspects. Academic Press. p. 348. ISBN   9780080472072.
  6. ↑ Alexandra Simperler, Stephen W. Watt, P. Arnaud Bonnet, William Jones, W. D. Samuel Motherwell (2006): "Correlation of melting points of inositols with hydrogen bonding patterns". CrystEngComm, volume 8, pages 589-600 doi : 10.1039/B606107A
  7. ↑ William R. Sherman, Mark A. Stewart, Mary M. Kurien, Sally L. Goodwin (1968): "The measurement of myo-inositol, myo-inosose-2 and scyllo-inositol in mammalian tissues". Biochimica et Biophysica Acta (BBA), volume 158, issue 2, pages 197-205 doi : 10.1016/0304-4165(68)90131-1
  8. 1 2 Irina Monnard, Thierry Bénet, Rosemarie Jenni, Sean Austin, Irma Silva-Zolezzi, Jean-Philippe Godin (2020): "Plasma and urinary inositol isomer profiles measured by UHPLC-MS/MS reveal differences in scyllo-inositol levels between non-pregnant and pregnant women". Analytical and Bioanalytical Chemistry, volume 412, pages 7871–7880. doi : 10.1007/s00216-020-02919-8
  9. ↑ Parthasarathy, L. K.; Seelan, R. S.; Tobias, C.; Casanova, M. F.; Parthasarathy, R. N. (2006). Mammalian inositol 3-phosphate synthase: its role in the biosynthesis of brain inositol and its clinical use as a psychoactive agent. Subcellular Biochemistry. Vol. 39. pp. 293–314. doi:10.1007/0-387-27600-9_12. ISBN   978-0-387-27599-4. PMID   17121280.
  10. ↑ Kiani AK, Paolacci S, Bertelli M (2021). "From Myo-inositol to D-chiro-inositol molecular pathways". European Review for Medical and Pharmacological Sciences . 25 (5): 2390–2402. doi:10.26355/eurrev_202103_25279. PMID   33755975.
  11. ↑ Tabrizi R, Ostadmohammadi V, Asemi Z (2018). "The effects of inositol supplementation on lipid profiles among patients with metabolic diseases: a systematic review and meta-analysis of randomized controlled trials". Lipids in Health and Disease . 17 (1): 123. doi: 10.1186/s12944-018-0779-4 . PMC   5968598 . PMID   29793496.
  12. ↑ Masaru Yamaoka, Shin Osawa, Tetsuro Morinaga, Shinji Takenaka, Ken-ichi Yoshida (2011): "A cell factory of Bacillus subtilis engineered for the simple bioconversion of myo-inositol to scyllo-inositol, a potential therapeutic agent for Alzheimer's disease". Microbial Cell Factories, volume 10, article number 69. doi : 10.1186/1475-2859-10-69
  13. ↑ "Phytic acid". www.phytochemicals.info. Archived from the original on 7 March 2018. Retrieved 2018-05-02.{{cite web}}: CS1 maint: unfit URL (link)
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