How can I draw axial and equatorial bonds in glucose?

1 Answer
Jun 15, 2015

You follow the steps below.

Explanation:

Step 1. Draw the Fischer projection of glucose.

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Step 2. Draw a cyclohexane chair, showing the axial and equatorial bonds.

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Replace "C-6" of the ring with an "O" atom (the "O" atom on "C-5" of glucose), and place the bulky "CH"_2"OH" group in the equatorial position of "C-5".

Step 3. Insert the "OH" groups on "C-2" to "C-4".

In the Fischer projection their orientations are in the order "right-left-right".

In the pyranose chair, the orientations will be "down-up-down".

Draw the "OH" groups on "C-2" and "C-4" in the "down" (equatorial) positions.

Draw the "OH" group on "C-3" in the "up" (equatorial) location.

Draw an "OH" below the ring (axial) on "C-1" for the α form. Draw it above the ring (equatorial) for the β form.

The chair form of α-D-glucopyranose is

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And the structure of β-D-glucopyranose is

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As you move around the β-glucose ring, you see that all the substituents are equatorial.