2302169 Chem Med Studt
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แบบฝึ กหัด Carbohydrate, Amino Acid and Peptide
(มีเฉลยบางข้ อท้ ายแบบฝึ กหัด)
1) Convert each compound to a Fisher projection and label each stereogenic center as R or S.
Br
COOH
1.1 H3 C
Br
H
1.2 H3 C
H 3 CH 2C
1.3
H
Cl
1.4
H 3CO OCH2 CH3
Cl
1.5
H
Br
CH3
H
Br
Cl
H3 C
CH2 CH3
H
1.6
H
CH2 CH 3
Br
Cl
Cl
H
Br
2) For D-arabinose
2.1 Draw its enantiomer.
2.3 Draw a diastereomer that is not an epimer.
2.2 Draw an epimer at C3.
carbonyl group.
2.4 Draw a constitutional isomer that still contains a
3) Draw a Haworth projection for each compound
3.1 β-D-talopyranose
3.3 α-D-galactopyranose
3.2 β-D-manopyranose
3.4 α-D-ribofuranose
4) D-Arabinose can exit in both pyranose and furanose forms.
4.1 Draw the α and β anomers of D-arabinofuranose.
4.2 Draw the α and β anomers of D-arabinopyranose.
5) Draw the products formed when α-D-gulose is treated with each reagent.
OH
5.1 CH3I, Ag2O
5.4 C6H5CH2OH, HCl
5.2 CH3OH, HCl
5.5 Ac2O, pyridine
OH
O
HO
OH
5.3 C6H5CH2Cl, Ag2O
D-gulose
6) What products are formed when each compound is subjected to a Kiliani-Fisher synthesis?
CHO
CHO
6.1
H
H
OH
OH
CH 2OH
OH
6.2
HO
HO
H
H
H
OH
CH 2OH
CHO
6.3
HO
HO
HO
H
H
H
H
OH
CH 2OH
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7) Identify the the compounds A-F in the following reactions.
OH OH
OH
O
7.1
HO
HO
CH 3I
O
O
HO
HO
OH
A
H3 O+
B + C + CH 3OH
Ag 2O
(Both anomers of B and C are f omed)
OH OH
O
7.2
CH 3I
HO
OH
H3 O+
D
E + F + CH 3OH
Ag 2O
O
HO
HO
(Both anomers of E and F are fomed)
HO O
OH
8) Deduce the structure of the disaccharide isomaltose from the following data.
[1] Hydrolysis yields D-glucose exclusively. [2] Isomaltose is cleaved with α-glucosidase enzyme
[3] Isomaltose is a reducing sugar.
[4] Methylation with excess CH3I, Ag2O and then hydrolysis with H3O+ forms two products:
OCH3
H3CO
H 3CO
OH
O
CH3O
OH
H3CO
H 3CO
O
CH3O
OH
9) Draw the structures of each amino acid at its isoelectric point.
9.1 alanine
9.3 aspartic acid
9.2 methionine
9.4 lysine
10) Draw the major form of each of the following amino acid at pH = 1.
10.1 threonine
10.3 aspartic acid
10.2 methionine
10.4 arginine
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11) Draw the organic products formed in each reaction.
O
11.1
NH3
(CH 3) 2CHCH 2CHCOOH
excess
Br
O
COOEt
[3] H3
11.3
O
OHC
COOEt
11.5
COOEt [2]
AcO
CH2 Br
O+,
H
H 3CO
[1] NH 4Cl, NaCN
[2] H3 O+
O
[1] NaOEt
11.2
N
H
11.4
N
H
COOEt
[1] NaOEt
[2] Cl(CH 2) 4NHAc
[3] H3 O+, heat
heat
[1] NH 4Cl, NaCN
NHAc
[2] H3 O+
12) Draw the structure of each peptide.
12.1 Phe-Ala
12.3 Lys-Gly
12.2 Gly-Gln
12.4 R-H
13) Name the peptide using both the three-letter and one-letter abbreviations of the component amino acids.
H 2N
H
N
O
N
H
O H
H CH 2CH 2COOH
OH
O
COOH
14) Draw the s-trans and s-cis conformations of the peptide bond in the dipeptide Ala-Ala.
15) Draw all the products formed in the following reaction.
O
Boc N
H
OH
+
O
H 2N
DCC
OH
H CH(CH3 )2
16) Draw all the steps in the synthesis of each peptide from individual amino acids
16.1 Gly-Ala
16.2 Phe-Leu
17) Write out the steps for the synthesis of each peptide using the Merrifield method
17.1 Ala-Leu-Phe-Phe
17.2 Phe-Gly-Ala-Ile
18) Devise a synthesis of each amino acid from acetaldehyde (CH3CHO).
18.1 glycine
18.2 alanine
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เฉลย Carbohydrate, Amino Acid and Peptide
H
Cl
R
Br
H
Cl S Br
1.6)
1.1), 1.3), 1.4) S; 1.2) R; 1.5) S,S;
CHO
H
OH
HO
H
2.1)
HO
2.2)
H
H
CH 2OH
CH 2OH
O
OH
H
3.2)
2.4)
O
HO
OH
OH
OH
CH 2OH
constitutional isomer
diastereomer
(but not epimer)
CH 2OH
O
OH
OH
OH
CH 2OH
OH
OH
CHO
H
OH
HO
H
2.3)
C3 epimer
enantiomer
3.1)
CHO
HO
OH
HO
H
OH
3.3)
OH
OH
CH 2OH
O
OH
HOH 2C
O
3.4)
OH
OH
OH
OH
OH
OH
OH
4.1) HOH 2C
OH
OH
O
HOH 2C
O
OH
OCH3
O
5.1)
H3 CO
H3 CO
OH
BnO
O
5.2)
+  anomer
HO
HO
+  anomer
6.1)
O
5.5)
AcO
7.1)
H 3CO
OCH 3
O
O
H 3 CO
H 3CO
AcO
OBn
CHO
H
OH
H
OH + C2 epimer
H
OH
CH 2OH
H 3CO
OCH 3
O
7.2)
H 3CO
H 3CO
H 3CO
OCH 3
O
H 3CO
OCH 3
H 3CO
OCH 3
O
O
D
H 3CO O
CHO
H
OH
HO
H
6.3) HO
H
+ C2 epimer
HO
H
H
OH
CH 2OH
OCH 3
O
OH
H 3CO
HO
H 3CO
H 3CO
H 3CO
E
OCH 3
HO
H3 CO
H 3 CO
OH
OCH 3
O
H 3CO
C
B
H 3CO
H3 CO
H 3 CO
OAc
CHO
H
OH
HO
H
6.2) HO
H
+ C2 epimer
H
OH
CH 2OH
A
H 3CO
OBn
OAc
HO
HO
Bn = C 6 H5 CH 2-
BnO
BnO
AcO
5.4)
OBn
O
OCH 3
OH
O
OH
OH
 anomer
5.3)
HO
OCH 3
OH
OH
OH
 anomer
 anomer
 anomer
O
OH
OH
OH
OH
OH
OH
H3 CO
O
4.2)
OH
H 3CO O
F
OH
OH
---5--H 3CO
OCH 3
O
7.2)
H 3CO
H 3CO
H 3CO
O
H 3CO O
H3CO
H 3CO
HO
OCH 3
O
OH
F
OH
9.3) aspartic acid
CO 2+H N C H
3
CH 2CH 2SCH3
CH 3
CO 2H
3N C H
+H
threonine
9.4) lysine
CO 2H 2N C H
CH 2CH 2CH2 CH 2 NH 3+
CO 2H
N
C H
3
10.3) pI = 5.41, +2 charge at pH 1
CO 2H
H 3N C H
aspartic acid
CH 2CO2 H
(CH 2) 3NH
H2 N
11.1) (CH 3) 2CHCH 2CHCO2 NH 4
+ NH 4 +Br -
11.2)
HO
NH 3
NH 2
O
11.3) HO2 C
CO 2H
11.4) HO
NH 2
NH 2
H 5C 6 H2 C
O
H
N
H 2N
O
12.2)
OH
H
N
H 2N
O
CH 3
H
N
O
H
N
12.4)
H2 N
14)
CH3
CH3
13) Gly-Asp-Glu or G-D-E
O
OH
N
H
H2 N
O
NH
H 3C
H3 C
s-tr ans
s-cis
15)
Boc
N
H
H
N
O
OH
O
O
O
OH
CH(CH3)2
+
H 2N
(CH3)2CH
N
H
NH 2
CH 2CHCO2 H
(CH 2) 4NH 2
H
N
C CO 2H
11.5)
2
H
H 2N
OH
CH 2CH 2CONH2
N
O
NH 2
O
OH
H
N
O
H2 N
methionine
CH 2CH 2SCH3
10.3) pI = 2.98, +1 charge at pH 1
NH 2
HO O
10.2) pI = 5.74, +1 charge at pH 1
CHOH
CH 3
HN
OH
OH
CH 2CO2 H
10.1) pI = 5.06, +1 charge at pH 1
12.1)
O
OH
9.2) methionine
CO 2+
H3N C H
CO 2+
H3N C H
CO 2H
H 3N C H
HO
HO
OCH 3
9.1) alanine
+
8)
E
D
+H
O
H 3CO O
H3CO
H 3CO
H 3CO
H 3CO
OH
HO
CH(CH3)2
OH
O
H
N
12.3)
H2N
O
O
OH