= Glucosamine
<Glucosamine> is an <amino sugar>, conventionally 2-amino-2-deoxy-D-<glucose>. Relative to the open-chain <glucose> reference structure, its carbon-2 <hydroxy group> is replaced by an <amino group>, with the corresponding stereochemical arrangement retained.<Nomenclature of Carbohydrates (Recommendations 1996) by Alan D. McNaught>[Section 2-Carb-14: D-glucosamine and amino-deoxy naming]{ref}
Replacing $\mathrm{OH}$ by $\mathrm{NH_2}$ removes one <oxygen> and adds one <nitrogen> and one <hydrogen>. Thus the neutral free base has <molecular formula> $\mathrm{C_6H_{13}NO_5}$, compared with $\mathrm{C_6H_{12}O_6}$ for <glucose>. This is structural bookkeeping, not a claim that every preparation is made by one replacement reaction.
<N-acetylglucosamine> further modifies that nitrogen. Distinguishing the two names matters when identifying a <polysaccharide>'s building blocks: an <acetyl group> changes chemical identity even though the six-carbon framework remains recognizable.<Nomenclature of Carbohydrates (Recommendations 1996) by Alan D. McNaught>[Section 2-Carb-25: amino-sugar nitrogen substitution]{ref}
Back to article page
