Question

Write Haworth formula of
$\alpha - d( - )$
fructofuranose. How are

proteins classified?


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Answer 1

Answer:

only the difference between real configuration and Haworth projection. The fructose has an arabino-pentofuranosyl configuration at its furanose 5-ring. So imagine the fructose firstly as beta-D-arabinofuranose and add then the hydroxymethyl goup at carbon 1 in alpha position. So you get an 1-alpha-(hydroxymethyl)-beta-D-arabinofuranose which represents beta-D-fructofuranose. Then condense the alpha-D-glucopyranose at carbon 1 of the 1-alpha-(hydroxymethyl)-beta-D-arabinofuranose and you get sucrose. The Haworth projection is somewhat confusing regarding the glycosidic bond, but the fructose is inverted in the Haworth formula. See also attached figure.