When heated to 100°C, n-idose undergoes a reversible loss of water and exists primarily as 1, 6-anhydro-D-idopvranose.

(a) Draw D-idose in its pyranose form, showing the more stable chair conformation of the ring.

(b) Which is more stable, ?-D-idopyranose or ?-D-idopyranose? Explain.

(c) Draw 1,6-anhydro-n-idopyranose in its most stable conformation.

(d) When heated to 100 °C under the same conditions as those used for D-idose, 1)-glucose does not lose water and does not exist in a 1, 6-anhydro form. Explain.

Transcribed Image Text:

Сно CH- но но- -H- HO- H- -HO- 100 °C Н H20 но- -H- но- H- -HO- H- ČH2OH OCH2 D-Idose 1,6-Anhydro-D-idopyranose