Converting Fischer structures to Haworth and chair forms

Start with the Fischer (Rosanoff) structure D-glucose

Form the pyranose ring n D: CH 2 OH at C5 goes up n L: CH 2 OH at C5 goes down 5

This is a D-sugar

Determine alpha or beta n If OH at C1 is on the same side of the ring as the CH 2 OH group, the sugar is beta n If the OH at C1 is on the opposite side of the ring as the CH 2 OH group, the sugar is alpha n Let’s make our example beta

The beta anomer Same side

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

Fischer structure D-glucose

Place remaining OH groups n 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

Beta-D-glucopyranose

Haworth to chair form