What OH groups are axial in β-D-altropyranose? Having a lot of trouble drawing the compound in chair and boat conformation.

It looks like none of the OH groups are in axial position and all are equatorial. I have found several different drawings of this compound and have become very confused.

1 Answer
Dec 26, 2016

Here's how I work it out.


The structures of D-altrose and D-Glucose are

Altrose and Glucose
(Adapted from Chemistry - Tutorvista.com)

The configuration of D-altrose differs from that of D-glucose at carbons 2 and 3.

In β-D-glucopyranose, all #"OH"# groups are equatorial.


Thus, in β-d-altropyranose, the #"OH"# groups on carbons 2 and 3 are axial.

I couldn't find an image of the molecule, so I drew the one below, omitting all H atoms except those on the ring.


The #"OH"# groups on carbons 2 and 3 are axial. The others are equatorial.