Chapter 24: Carbohydrates

Question 1

Excess Ac2O, Pyridine with aldoses/ketoses

Answer 1

Ether Formation

Acylated all Hydroxide Groups

Question 2

Excess CH3I, Ag2O with aldoses/ketoses

Answer 2

Williamson Ether Synthesis

-alkoxide formed through Ag2O, attacks alkyl halide

Question 3

ROH, HCl with aldoses/ketoses

Answer 3

Glycoside Formation

Converts anomeric carbon to full acetyl (glycoside) instead of hemiacetyl

Question 4

NaBH4, H2O with Aldose only

Answer 4

Reduction

-reduces carbonyl to alcohol/ Alditol, can only reduce the open form

Question 5

Br2, H2O, pH=6 with aldoses

Answer 5

Oxidation

-oxidized open form to have carboxylic acid, only to aldonic acid (not ketoses)

Question 6

HNO3, H2O, Heat with aldoses

Answer 6

Aldaric Acid

-convert both ends of sugar to carboxylic acid

Question 7

1) HCN 2)H2, Pd/BaSO4, H2O with aldoses

Answer 7

Killani-fischer Synthesis

• CN attacks carbonyl and forms two enatiomers
• CN reduces and hydrolyzed, reforms aldehyde
• adds one carbon

Question 8

NH2OH, AC2O, OMe with aldoses/ketoses

Answer 8

• oxime forms with NH2OH, dehydration forms cyanohydrin
• base deprotenated C2 OH, releases nitrile
• takes away one carbon