synthesis of perbenzoylated carbohydrates in preparation for anthocyanin pigment characterization...
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Synthesis of Perbenzoylated Carbohydrates in Preparation for
Anthocyanin Pigment Characterization
Brandon Lew
March 15, 2006
Introduction
• Purpose:
To develop a technique for carbohydrate characterization through NMR so that anthocyanin carbohydrate tails may be characterized.
Anthocyanins
http://www.mariquita.com/images/photogallery/strawberries.jpg http://www.personal.psu.edu/staff/m/h/mhl100/images/blueberries.jpg
Carbohydrate Tails
O+
OH
H
OH
OH
R2
OH
R1
35
7
3' 4'
5'
Anthocyanidin Base
O
HOH
OH
OH
H
H
OH
OH
H
Anthocyanin Characterization
• NMR of anthocyanins
Seeram et al. 2002
• Separation of tails
Takeoka et al. 2005
• Combine to perform NMR on separated tails
Carbohydrates
ChairChain
C 4
C 3
C 2
C 1
O
C 5
HOH
OH
OH
H
H
OH
H
C 6
OH
H
OH
C 2
C 3
OHH
C 4 OHH
C 5
C 6
H
OHH
OHH
HOH
C 1
OHH
Can Twist,Resulting inBeta-Anomer
In Beta-Anomer,These are Flipped
Perbenzoylation
• Levene and Meyer (1927) Glucose
• D’Accorso et al. (1981) NMR data of many monosaccharides
R
O
R
O
Perbenzoylation (Protocol 1)
O
HOH
OH
OH
H
H
OH
H OH
H
O
H
H
H
H
OBz
HOBz
BzO
BzO
OBz
O
Cl
Pyridine
100 oC
β-glucose Perbenzoylated-β-glucose
Purification
• Thin-layer chromatography (TLC)
• Column chromatography
• High-pressure liquid chromatography (HPLC)
http://www.hamline.edu/depts/chemistry/facility/images/hplc.jpg
Nuclear Magnetic Resonance Spectroscopy (NMR)
1H/13CEM radiation
Excited State
Ground StateRadio wave Detector
Magnetic Field
Protocol 1 Results: 1H NMR of perbenzoylated β glucose
Protocol 1 Results: HPLC of perbenzoylated maltose
Protocol 1 Results: 13C NMR of perbenzoylated maltose
Perbenzoylation (Protocol 2)
O
HOH
OH
OH
H
H
OH
H OH
H
O
H
H
H
H
OBz
HOBz
BzO
BzO
OBz
O
Cl
Pyridine, CHCl3
0 oC
β-glucose Perbenzoylated-β-glucose
Protocol 2 Results: 1H NMR of perbenzoylated β glucose
Protocol 2 Results: HPLC of perbenzoylated β glucose
Procedure 2 Results: 1H NMR of perbenzoylated α glucose
Conclusion• Protocol 1 – contaminated
• Some disaccharides selectively benzoylated
O
HOH
OH
OH
H
H
OH
H OH
H
O
H
H
H
H
OBz
HOBz
BzO
BzO
OBz
O
Cl
Pyridine
100 oC
β-glucose Perbenzoylated-β-glucose
Conclusion• Protocol 2 – purer, quicker
• Perbenzoylation works for characterization
O
HOH
OH
OH
H
H
OH
H OH
H
O
H
H
H
H
OBz
HOBz
BzO
BzO
OBz
O
Cl
Pyridine, CHCl3
0 oC
β-glucose Perbenzoylated-β-glucose
Future Work
• Use perbenzoylation to characterize carbohydrate tails of anthocyanins
• Anthocyanins differ by their tails
• Important for developing anti-oxidant food additives
Acknowledgements
• Dr. Matachek
• Hamline University
• Ms. Fruen
• Ms. Richter, Bill Mitchell
• Team Research
Synthesis of Perbenzoylated Carbohydrates in Preparation for
Anthocyanin Pigment Characterization
Brandon Lew
March 15, 2006