α-Cyclodextrin

α-Cyclodextrin (alpha-cyclodextrin), sometimes abbreviated as α-CD, is a hexasaccharide derived from glucose. It is related to the β- (beta) and γ- (gamma) cyclodextrins, which contain seven and eight glucose units, respectively. All cyclodextrins are white, water-soluble solids with minimal toxicity. Cyclodextrins tend to bind other molecules in their quasi-cylindrical, lipophilic interiors. The compound is of wide interest because it exhibits host–guest properties, forming inclusion compounds.[2] This inclusion (and release) behavior leads to applications in medicine.[3]

Α-Cyclodextrin
Names
IUPAC name
cyclomaltohexaose
Systematic IUPAC name
cyclohexakis-(1→4)-α-D-glucopyranosyl
Other names
Cyclohexaamylose
Cyclohexadextrin
Cyclomaltohexose
α-Cycloamylose
α-Dextrin
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
DrugBank
ECHA InfoCard 100.029.995
EC Number
  • 233-007-4
KEGG
UNII
  • InChI=1S/C36H60O30/c37-1-7-25-13(43)19(49)31(55-7)62-26-8(2-38)57-33(21(51)15(26)45)64-28-10(4-40)59-35(23(53)17(28)47)66-30-12(6-42)60-36(24(54)18(30)48)65-29-11(5-41)58-34(22(52)16(29)46)63-27-9(3-39)56-32(61-25)20(50)14(27)44/h7-54H,1-6H2/t7-,8-,9-,10-,11-,12-,13-,14-,15-,16-,17-,18-,19-,20-,21-,22-,23-,24-,25-,26-,27-,28-,29-,30-,31-,32-,33-,34-,35-,36-/m1/s1
    Key: HFHDHCJBZVLPGP-RWMJIURBSA-N
  • C([C@@H]1[C@@H]2[C@@H]([C@H]([C@H](O1)O[C@@H]3[C@H](O[C@@H]([C@@H]([C@H]3O)O)O[C@@H]4[C@H](O[C@@H]([C@@H]([C@H]4O)O)O[C@@H]5[C@H](O[C@@H]([C@@H]([C@H]5O)O)O[C@@H]6[C@H](O[C@@H]([C@@H]([C@H]6O)O)O[C@@H]7[C@H](O[C@H](O2)[C@@H]([C@H]7O)O)CO)CO)CO)CO)CO)O)O)O
Properties
C36H60O30
Molar mass 972.846 g·mol−1
Appearance white solid
Melting point 507 °C (945 °F; 780 K) at fast heating rates, decomposition below 300 °C for conventional heating [1]
14.5 g/100 mL
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Structure
Main article: cyclodextrin § Structure

In α-cyclodextrin, the six glucose subunits are linked end to end via α-1, 4 linkages. The result has the shape of a tapered cylinder, with six primary alcohols on one face and twelve secondary alcohol groups on the other. The exterior surface of cyclodextrins is somewhat hydrophilic whereas the interior core is hydrophobic.

Three representations of α-cyclodextrin.

Applications

α-Cyclodextrin is marketed for a range of medical, healthcare, and food and beverage applications. For drug delivery, this cyclodextrin confers aqueous solubility to hydrophobic drugs and stability to labile drugs.[4]

Crystal structure of a rotaxane with an α-cyclodextrin macrocycle.[5]

Synthesis

Cyclodextrins are natural starch-conversion products. For industrial use, they are manufactured by enzymatic degradation from vegetable raw materials, such as corn or potatoes. First, the starch is liquified either by heat treatment or using α-amylase. Then cyclodextrin glycosyltransferase (CGTase) is added for enzymatic conversion. CGTases produce diverse cyclodextrins. The selectivity of the synthesis can be improved by the addition of specific guests.[3]

See also

References
  1. Gatiatulin, Askar (2022), "Determination of Melting Parameters of Cyclodextrins Using Fast Scanning Calorimetry", Int. J. Mol. Sci., 23 (21): 13120, doi:10.3390/ijms232113120, PMC 9655725
  2. Zhichang Liu; Siva Krishna Mohan Nalluria; J. Fraser Stoddart (2017). "Surveying macrocyclic chemistry: from flexible crown ethers to rigid cyclophanes". Chemical Society Reviews. 46 (9): 2367–2650. doi:10.1039/c7cs00185a. PMID 28462968.
  3. József Szejtli (1998). "Introduction and General Overview of Cyclodextrin Chemistry". Chem. Rev. 98 (5): 1743–1754. doi:10.1021/cr970022c. PMID 11848947.
  4. Thomas Wimmer (2012). "Cyclodextrins". Ullmann's Encyclopedia of Industrial Chemistry. Wiley-VCH. doi:10.1002/14356007.e08_e02. ISBN 978-3527306732.
  5. Stanier, Carol A.; O'Connell, Michael J.; Anderson, Harry L.; Clegg, William (2001). "Synthesis of fluorescent stilbene and tolan rotaxanes by Suzuki coupling". Chemical Communications (5): 493–494. doi:10.1039/b010015n.
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