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Ribose is cyclized to the hemiacetal -D-ribofuranose. Draw a curved-arrow mechanism to show the cyclization step. Ribose is cyclized to the hemiacetal <font face= symbol ></font>-D-ribofuranose. Draw a curved-arrow mechanism to show the cyclization step.

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The hydroxy group on carbon 4 ...

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When -D-glucopyranose is dissolved in water, mutarotation occurs. What has happened?


A) The carbohydrate has converted completely to -D-glucopyranose.
B) The carbohydrate has converted to a mixture of -D-glucopyranose and -D-glucopyranose.
C) The carbohydrate has converted to its enantiomer.
D) The carbohydrate has changed from D- to L-configuration.

E) A) and B)
F) B) and C)

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Given the chair conformation of a monosaccharide, provide the open-chain form. Given the chair conformation of a monosaccharide, provide the open-chain form.

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Translate the chair conformation to the ...

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A D-aldohexose is treated with HNO3 to give an optically inactive aldaric acid. Deduce the Fischer projection of the D-aldohexose. There is more than one correct answer.

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Dilute nitric acid oxidizes both primary...

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Assign the R/S configuration for each of the asymmetric carbons in the carbohydrate. Assign the R/S configuration for each of the asymmetric carbons in the carbohydrate.

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Recall in a Fischer projection that the ...

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The Ruff degradation of two aldopentoses gives D-threose. Deduce the structures of the two aldopentoses. The Ruff degradation of two aldopentoses gives D-threose. Deduce the structures of the two aldopentoses.

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The Ruff degradation will remove the top carbon of an aldopentose. Carbon 2 of the aldopentose will become the aldehyde carbon in the threose. Working backward, this means the aldopentoses must have been D-lyxose or D-xylose. 11edaded_7d2a_6cba_a31a_cbc51319afc8_TBMC1048_00

A D-aldopentose forms two aldohexoses, A and B, after a Kiliani-Fisher synthesis. Aldohexose A is oxidized to an optically inactive aldaric acid, while aldohexose B is oxidized to an optically active aldaric acid. The aldopentose can also be oxidized to an optically inactive aldaric acid. Deduce the structures of the aldopentose and the two aldohexoses.

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The Kiliani-Fischer synthesis adds a carbon to an aldopentose to generate the two aldohexoses. The aldopentose and aldohexoses can be oxidized to aldaric acids, where the top and bottom carbons of the Fischer projections are both carboxylic acids. The aldopentose gives an optically inactive aldaric acid, so it must have been either D-ribose or D-xylose, since both aldaric acids formed from these have a plane of symmetry bisecting carbon 3. 11edaded_7d2a_93ce_a31a_71898c2d0f5f_TBMC1048_00 ​ The two aldohexoses formed from the Kiliani-Fischer synthesis of ribose would be D-allose and D-altrose. 11edaded_7d2a_93cf_a31a_1d025a5c5348_TBMC1048_00 ​ The aldaric acid made from D-allose would be optically inactive, while the aldaric acid made from D-altrose would be optically active. This matches the data given. Let's look at the other possibility. The two aldohexoses made from the Kiliani-Fischer synthesis of xylose would be D-gulose and D-idose. 11edaded_7d2a_93d0_a31a_37990793ca11_TBMC1048_00 ​ The aldaric acids made from gulose and idose will both be optically active, which doesn't match the data given, so we can conclusively identify the aldopentose as D-ribose. Aldohexose A is D-allose and aldohexose B is D-altrose.

Identify the relationship between the two carbohydrates. Select all that apply. Identify the relationship between the two carbohydrates. Select all that apply. A) enantiomer B) diastereomer C) anomer D) epimer


A) enantiomer
B) diastereomer
C) anomer
D) epimer

E) B) and C)
F) A) and D)

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Classify the carbohydrate, then indicate the chiral carbons with an asterisk. How many possible stereoisomers can exist for this carbohydrate? Classify the carbohydrate, then indicate the chiral carbons with an asterisk. How many possible stereoisomers can exist for this carbohydrate?

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A carbohydrate with a ketone group is ca...

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Convert the line-and-wedge structure into a Fischer projection, then assign as a D- or L-carbohydrate. Convert the line-and-wedge structure into a Fischer projection, then assign as a D- or L-carbohydrate.

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You might find it easier to assign the c...

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Classify the carbohydrate, then indicate the chiral carbons with an asterisk. How many possible stereoisomers can exist for this carbohydrate? Classify the carbohydrate, then indicate the chiral carbons with an asterisk. How many possible stereoisomers can exist for this carbohydrate?

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A carbohydrate with an aldehyde group is...

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D-Altrose can be transformed to another aldose and 2-ketose upon treatment with base. Draw the structure of the aldose and 2-ketose. D-Altrose can be transformed to another aldose and 2-ketose upon treatment with base. Draw the structure of the aldose and 2-ketose.

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The alpha proton can be deprotonated and...

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Identify the relationship between the two carbohydrates. Select all that apply. Identify the relationship between the two carbohydrates. Select all that apply. A) enantiomer B) diastereomer C) anomer D) epimer


A) enantiomer
B) diastereomer
C) anomer
D) epimer

E) All of the above
F) A) and D)

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The disaccharide maltose is shown below. a. Classify the disaccharide as a reducing or nonreducing sugar and explain why. b. Identify the glucoside linkage in maltose and classify each as either alpha or beta. c. Name the monosaccharides formed when maltose is hydrolyzed in aqueous acid. The disaccharide maltose is shown below. a. Classify the disaccharide as a reducing or nonreducing sugar and explain why. b. Identify the glucoside linkage in maltose and classify each as either alpha or beta. c. Name the monosaccharides formed when maltose is hydrolyzed in aqueous acid.

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a. Maltose is a reducing sugar since car...

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Two aldohexoses (D-galactose and D-talose) are formed from a Kiliani-Fischer synthesis. Deduce the starting material. Two aldohexoses (D-galactose and D-talose) are formed from a Kiliani-Fischer synthesis. Deduce the starting material.

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The Kiliani-Fischer synthesis adds a car...

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Draw an enantiomer of the carbohydrate. Assign the D- or L-configuration to each. Draw an enantiomer of the carbohydrate. Assign the D- or L-configuration to each.

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The enantiomer is simply the mirror imag...

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Predict the major organic product for the reaction. If more than one isomer is formed, just draw one. Predict the major organic product for the reaction. If more than one isomer is formed, just draw one.

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The monosaccharide will react with methanol under acidic conditions to give a cyclic acetal. None of the other hydroxy groups will be converted to an ether. Both the alpha and beta anomers will be formed. 11edaded_7d2a_459f_a31a_616c063c323e_TBMC1048_00

Most hexoses found in nature are D-carbohydrates. Comparing a D-carbohydrate with the Cahn-Ingold-Prelog system of nomenclature, select the true statement.


A) A D-carbohydrate will have R configuration.
B) A D-carbohydrate will have S configuration.
C) There is no relationship between the D,L system and the R/S configuration.

D) B) and C)
E) All of the above

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A methyl D-glucopyranoside contains a methoxy group on which carbon of glucose? Explain the difference between a pyranoside and a pyranose.

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A pyranose is a hemiacetal, wh...

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A D-aldotetrose reacts with NaBH4 to give an optically active product. Deduce the structure of the D-aldotetrose and the product.

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There are two possible D-aldotetroses, e...

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