Question

Convert the Fischer projection to the Haworth projection of the B-pyranose form by moving the substituents to the appropriate positions. The anomeric carbon is shown. EK Cyclization } CH2OH Answer Bank CH,OH OH H

Answer 1

ANSWER:

While converting Fischer projection to Haworth projection, the groups on the left in Fischer projection stay on top of the vertical lines in Haworth projection and the groups on the right side in Fischer projection go to the bottom of the vertical lines in Haworth projection. However the lowermost CH2OH group always stays on top of a vertical line in Haworth projection.

In cyclization, the O atom on the lowermost chiral carbon(C5) attacks on the carbon of CHO group at the top. This converts the carbon into a chiral carbon. If H atom on this carbon stays on the left in Fischer projection, it is called α- isomer and if this H stays on the right side of the Fischer projection, it becomes β-isomer. Further in Haworth projection, the carbon atom to the immediate right to the O atom is numbered 1 and the numbering then runs clockwise.

Сп, оң HH 다 이매 | Hug A 애 HOH & I & II OH 애 ㅗ애 Ho :: H 애 + 앵 «н, он B-pyranose form 왜애 B- isomer