Organic Chemistry
9th Edition
ISBN: 9781305080485
Author: John E. McMurry
Publisher: Cengage Learning
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Chapter 25.SE, Problem 48AP
Interpretation Introduction
Interpretation:
The pyranose form of β-anomer of D-talose is to be drawn. The ring substituents are to be identified as axial or equatorial.
Concept introduction:
The pyranose form is a cyclic hemiacetal form with a six membered ring formed by the nucleophilic addition of the –OH group on C5 to the C1 carbonyl group. The furanose form is a cyclic hemiacetal form with a five membered ring formed by the nucleophilic addition of the –OH group on C5 to the C2 carbonyl group.
The orientation of –OH group differs in α- and β- anomers. In α- anomer the OH on C1 is cis to the –OH at the lowest chirality center in Fischer projection, while in β- anomer the –OH on C1 is trans to the –OH at the lowest chirality center in Fischer projection.
D sugars have the –O- at C adjacent to CH2OH on the right in the uncoiled form while L sugars have the -O- at C adjacent to CH2OH on the left.
To draw:
The pyranose form of β-anomer of D-talose and to identify the ring substituents as axial or equatorial.
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Carbohydrates. Determination of the extent of branching in glycogen.
The amount of branching (number of α 1⟶ 6 glycosidic bonds) in glycogen can be determined by the following procedure. A sample of glycogen is exhaustively methylated-treated with a methylating agent (methyl iodide) that replaces the hydrogen of every sugar hydroxyl with a methyl group, converting –OH to –OCH3. All the glycosidic bonds in the treated sample are then hydrolyzed in aqueous acid, and the amounts of α -D-2,3-di-O-methylglucopyranose and α -D-2,3,6-tri-O-methylglucopyranose formed are measured.
1- Draw the cyclic structure of α-D-glucopyranose, α-D-2,3-di-O-methylglucopyranose and α-D-2,3,6-tri-O-methylglucopyranose, including the numbering of carbon atoms.
2- Which of α-D-2,3-di-O-methylglucopyranose or α-D-2,3,6-tri-O-methylglucopyranose represents a glucose unit in glycogen which was originally carrying a α 1⟶ 6 glycosidic bond? Explain.
Identify the anomeric carbon.
Identify the glycosidic linkage.
Lactose
ОН ОН
OH
HO
HO,
HO
OH
Which of the following is the correct pair of monosaccharides needed 2
to form the given glycoside? *
CH2OH
CH-OH CH2OH
OH
он
он
OH
OH
a-D-fructofuranose & B-D-glucopyranose
a-D-sorbofuranose & B-D-allopyranose
a-D-mannofuranose & B-D-glucopyranose
O a-D-sorbofuranose & B-D-galactopyranose
Chapter 25 Solutions
Organic Chemistry
Ch. 25.1 - Prob. 1PCh. 25.2 - Prob. 2PCh. 25.2 - Prob. 3PCh. 25.2 - Prob. 4PCh. 25.2 - Prob. 5PCh. 25.3 - Prob. 6PCh. 25.3 - Prob. 7PCh. 25.4 - Prob. 8PCh. 25.4 - Prob. 9PCh. 25.4 - Prob. 10P
Ch. 25.5 - Prob. 11PCh. 25.5 - Prob. 12PCh. 25.5 - Prob. 13PCh. 25.5 - Prob. 14PCh. 25.5 - Prob. 15PCh. 25.6 - Prob. 16PCh. 25.6 - Prob. 17PCh. 25.6 - Prob. 18PCh. 25.6 - Prob. 19PCh. 25.6 - Prob. 20PCh. 25.6 - Prob. 21PCh. 25.6 - Prob. 22PCh. 25.6 - Prob. 23PCh. 25.7 - Prob. 24PCh. 25.8 - Show the product you would obtain from the...Ch. 25.SE - Prob. 26VCCh. 25.SE - Prob. 27VCCh. 25.SE - Prob. 28VCCh. 25.SE - Prob. 29VCCh. 25.SE - Prob. 30MPCh. 25.SE - Prob. 31MPCh. 25.SE - Glucosamine, one of the eight essential...Ch. 25.SE - D-Glicose reacts with acetone in the presence of...Ch. 25.SE - Prob. 34MPCh. 25.SE - Prob. 35MPCh. 25.SE - Prob. 36APCh. 25.SE - Prob. 37APCh. 25.SE - Prob. 38APCh. 25.SE - Prob. 39APCh. 25.SE - Prob. 40APCh. 25.SE - Assign R or S configuration to each chirality...Ch. 25.SE - Prob. 42APCh. 25.SE - Prob. 43APCh. 25.SE - Prob. 44APCh. 25.SE - Prob. 45APCh. 25.SE - Prob. 46APCh. 25.SE - Prob. 47APCh. 25.SE - Prob. 48APCh. 25.SE - Prob. 49APCh. 25.SE - Prob. 50APCh. 25.SE - Prob. 51APCh. 25.SE - Prob. 52APCh. 25.SE - Prob. 53APCh. 25.SE - Prob. 54APCh. 25.SE - Prob. 55APCh. 25.SE - Prob. 56APCh. 25.SE - Prob. 57APCh. 25.SE - Prob. 58APCh. 25.SE - Prob. 59APCh. 25.SE - Prob. 60APCh. 25.SE - Prob. 61APCh. 25.SE - Prob. 62APCh. 25.SE - Prob. 63APCh. 25.SE - D-Mannose reacts with acetone to give a...Ch. 25.SE - Prob. 65APCh. 25.SE - Prob. 66APCh. 25.SE - Prob. 67APCh. 25.SE - Prob. 68APCh. 25.SE - Prob. 69APCh. 25.SE - Prob. 70APCh. 25.SE - Prob. 71AP
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