25.8: The Eight Essential Monosaccharides

Organic Chemistry · LibreTexts

0%

Contents

    Text

    Size
    100%
    Theme
    Typeface
    Line length
    Spacing

    From LibreTexts, under CC BY-SA 4.0, as the source states it; its equations are written in TeX, which the PDF shows typeset. This page at LibreTexts.

    Objectives

    1. identify and draw the eight essential monosaccharides

    Eight monosaccharides are required for the proper functioning of human beings. Although they are typically supplied through a healthy diet, they can be biosynthesized if required. The eight monosaccharides are L-fucose, D-galactose, N-acetyl-D-glucosamine, N-acetyl-D-galactosamine, D-glucose, D-mannose, N-acetyl-D-neuraminic acid, and D-xylose.

    D-Galactose, D-Glucose, and D-Mannose are commonly found aldohexoses:

    clipboard_eca1b46e861603087072b1af01964529b.png

    D-Xylose is a common aldopentose.

    25.4.1_problem_answer.svg

    D-Xylose

    L-Fucose is a deoxy sugar. Fucose is is the monosaccaride L-galactose with the -OH group on C6 replaced with an -H.

    fucose.png

    N-acetylgalactosamine and N-acetylglucosamine are derivatives where the corresponding amino sugars have been converted to amides by N-acylation. Amino sugars have had their -OH groups at C2 replaced by an -NH2.

    clipboard_e3caad9a15abd877386d3a5185bb3a9d2.png

    N-Acetylneuraminic acid is nine carbon sugar created by an aldol reaction between N-acetymannosamine and pyruvate. N-acetylneuaminic acid forms a pyranose ring by a intramolecular hemiacetal formation between the -OH on C6 and the ketone functional group in the pyruvate moiety.

    clipboard_ea2a2f4c7d668d4262b8e252617bbce06.png

    Exercise \(\PageIndex{1}\)

    1) Please show the mechanism of the aldol reaction between N-acetylmannosamine and pyruvate ‍to form neuraminic acid.

    Illustration

    Answer

    1)

    fucose.png

    25.8: The Eight Essential Monosaccharides is shared under a CC BY-SA 4.0 license and was authored, remixed, and/or curated by Steven Farmer & Dietmar Kennepohl.