Converting Fischer structures to Haworth and chair forms

1. Converting Fischer structures to Haworth and chair forms

2. Start with the Fischer (Rosanoff) structure D-glucose

3. 5 Form the pyranose ring • D: CH2OH at C5 goes up • L: CH2OH at C5 goes down

4. This is a D-sugar

5. Determine alpha or beta • If OH at C1 is on the same side of the ring as the CH2OH group, the sugar is beta • If the OH at C1 is on the opposite side of the ring as the CH2OH group, the sugar is alpha • Let’s make our example beta

6. Same side The beta anomer

7. What remains to be done? • We need to know the configuration of the OH groups at carbons 2, 3, and 4 • How do we do this? • Go back to the Fischer (Rosanoff) projection • Then lay it over on it’s side to the right

8. Fischer structure D-glucose

9. Place remaining OH groups • Put the remaining OH groups on the Haworth ring at C2, C3, and C4 in the same orientation (up or down) as they are in the leaned over Fischer/Rosanoff structure

10. Beta-D-glucopyranose

11. Haworth to chair form