1 (618)

Prévia do material em texto

Solutions for Carbohydrates and Nucleic Acids
CH2OCH3
OCH3
CH3OH
HOCH3
H
CH3OH2C O
H3O+
Ag2OOHOH2C
H
OH H
H HO
OH
CH2OH
OCH3H
OHH
CH2OCH3
HCH3O
C O
CH2OCH3
D-fructose
CH3OH +
(c) Determining that the open chain form of fructose is a ketone at C-2 with a free OH at C-5 shows that 
fructose exists as a furanose hemiacetal.
(b) acidic hydrolysis
(a)
40
1
1
2
3
6
4
5
2
3
4
5
6
CH2OH
C O
HC O
H3O+
CH2OH
H OH
CHO
O
CH2OH
OCH3
H
OH
H
CH2OH O
CH2OH
C O
HC O
HIO4
H3O+
H2C OH
CHO
OCH3
O O
OH
CH2OH
H
OCH2OH
H
OH H
H HO
OCH3
CH2OH
C OH
O
H
2 HIO4
H
H OCH3
HO O
OH
OH
H
CH2OH
formic acid
41
(a)
methyl β-D-fructopyranoside
+
+
methyl β-D-fructofuranoside
D-glyceraldehyde
(b)
+
Production of one equivalent of formic acid, and two fragments containing two and three carbons 
respectively, proves that the glycoside was in a six-membered ring.
1
2
34
5
6
1
2
34
5
6
1
2
3
4
5
6
1
234
5 6
1
23
4
5
6
1
2
3
5
6
excess
CH3I
613