Carbohydrate

1
Carbohydrate

• You will need to memorize the structures of the
  following monosaccharides

??? D ????? ???? OH ???????? ??? CH2OH ??
????? ?????? ????? Dextro ?? ?? ????? ??????
????? ?? ????? ????? ??????.
2
L Levo ????? ?? ???????? ???? ??? OH ???
??????? ?? ????? ??????.????? ?? ??? isomers ??
???????? ???????? 2n ??? n ?? ??? asymmetric
carbons.
3
II. Glucose

• Structure elucidation of glucose
• 1- Molecular formulae C6H12O6
• 2-

The reaction indicate that glucose contain
carbonyl groups
4

• 3- Mild oxidation of glucose with bromine water
  gives gluconic acid, also glucose gives positive
  with tollens reagent, this means that glucose
  contains CHO group.
• 4- Mild oxidation of glucose gives gluconic
  acid

5

• 5-Strong oxidation gives glucaric acid (sacchric
  acid)

This reaction indicates that glucose contain
terminal primary alcohol
6

• 6-

The above reaction showed that glucose is not
branched
7

• 7-

The reaction shows that glucose contains five OH
groups
8

• 8- glucose react with HCN to give cyanohydrin
  which gives heptanoic acid on hydrolysis
  followed by heating with HI

9

• From above reactions, glucose has the
  following structure.

• ???? ?? ????????? ??????? ???????? ????? ?????
  ?????
• ??????Glucose ????? ???? ???? ?? ???? ???
  ???????
• Glucose ????? ????? ????? ????? Osazone ?????
• ????????? ???? ??? ???? ????? ???????? ???
  ?????? ???? .

10

• Action of phenylhydrazine on glucose and fructose
  (formation of Osazone)
• (A) Glucose

11

• (B) Fructose

12

• Question
• write on the following
• Action of phenylhydrazine on glucose.
• Glucose and fructose give the same osazone.
• Complete the following equation
• Glucose 3 PhNHNH2

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Conversion of glucose to fructose or conversion
of aldoses to ketoses