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User:Benjah-bmm27/degree/3/MCG

From Wikipedia, the free encyclopedia

Carbohydrates, MCG

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Important functions and applications

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Common sugars

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Carbohydrate structures and conformations

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Hemiacetals and mutarotation

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  • Hemiacetal formation
    • alcohol + aldehyde → hemiacetal
    • acid promotes forward reaction, base promotes reverse
    • new chiral centre formed
    • In monosaccharides, the new chiral centre is called the anomeric carbon
  • Mutarotation of hemiacetals
    • α and β anomers of monosaccharides interconvert
    • α hemiacetal → aldehyde + alcohol → β hemiacetal
    • In solution, glucose is:
      • 36 % α-D-glucopyranose
      • 63 % β-D-glucopyranose
      • 0.003 % open chain aldehyde
      • negligible proportions exist as α-D-glucofuranose and β-D-glucofuranose

Ring conformation

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  • For glucose, 4C1 conformation preferred to 1C4 as the former has all equatorial groups, latter has all axial

Anomeric effect

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Protecting groups

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For alcohols

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Glycosylation reactions

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