Question 1

Draw a structure of S-isopropyl butanethioate.

Accepted Answer

A thioate indicates a thioester. Butanethioate indicates that the carbonyl is attached to a four-carbon chain. The S-isopropyl indicates an isopropyl group is attached directly to the sulfur. The structure is:

Question 2

Draw a structure of S-butyl cyclohexanecarbothioate.

Accepted Answer

A thioate indicates a thioester. A carbothiate indicates that the thioester is attached to a ring. The cyclohexane indicates a six-carbon ring. The S-butyl indicates a butyl group is attached directly to the sulfur. The structure is:

Question 3

Give the IUPAC and common name of the compound.

Accepted Answer

In systematic IUPAC naming, the thioester will have the parent name benzothioate, where the "thio" is inserted in the middle of "benzoate" to denote a thioester. A methyl group is attached directly to the sulfur, so the name will be S-methyl benzothioate.
In common naming, the thioesters will add the prefix -thio before the parent name and an S-prefix before the name of the alkyl group bonded to the sulfur. Thus, the common name is S-methyl thiobenzoate.

Question 4

What is the classification of the compound?

Accepted Answer

The compound contains two phosphate groups attached to different carbon atoms, indicating it is a phosphate diester.

Question 5

Bisphosphoglycerate mutase catalyzes the conversion of 1,3-bisphosphoglycerate to 2,3-bisphosphoglycerate. Identify the phosphorus containing functional groups in 1,3-bisphosphoglycerate, then characterize each group as either a phosphate monoester, phosphate diester, phosphate anhydride, or pyrophosphate monoester.

Accepted Answer

The answer of Bisphosphoglycerate mutase catalyzes the conversion of 1,3-bisphosphoglycerate...

Question 6

RNA can undergo spontaneous hydrolysis in basic solutions to form the cyclic compound below. Identify the phosphorus groups in both structures as either a phosphate monoester, phosphate diester, phosphate anhydride, or pyrophosphate monoester. Then propose a curved-arrow mechanism showing how the cyclic group can be formed.

Accepted Answer

The answer of RNA can undergo spontaneous hydrolysis in basic...

Question 7

An acyl phosphate is an example of a mixed anhydride of a phosphoric and carboxylic acid. Draw the expected products of the acyl phosphate reacting with CH₃NH₂.

Accepted Answer

The answer of An acyl phosphate is an example of...

Question 8

Glutathione is a coenzyme consisting of the tripeptide Glu-Cys-Gly. The first step of the synthesis of glutathione is catalyzed by glutamyl cysteine synthetase, where glutamate reacts with ATP to form an acyl phosphate. In the second step, cysteine reacts with the acyl phosphate to form $\gamma$-Glu-Cys and phosphate ion. Note, the $\gamma$-Glu indicates the reaction occurs on the sidechain.
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Draw the acyl phosphate formed in the first step, and then draw a plausible curved-arrow mechanism showing how the acyl phosphate can be converted to $\gamma$-Glu-Cys.

Accepted Answer

The answer of Glutathione is a coenzyme consisting of the...

Question 9

Aspartate reacts with ATP to give an unknown product and pyrophosphate. Draw the structure of the unknown product.

Accepted Answer

The answer of Aspartate reacts with ATP to give an...

Question 10

Describe the expected splitting pattern for the phosphorus resonance in the structure.

Accepted Answer

The answer of Describe the expected splitting pattern for the...

Question 11

Given the phosphate diester, predict the splitting patterns for the hydrogens labeled a, b, and c. Assume the coupling constants for H-H and P-H splitting are the same.

Accepted Answer

The answer of Given the phosphate diester, predict the splitting...

Question 12

Predict the major organic product for the reaction. If there is no reaction, write NR and explain why.

Accepted Answer

The answer of Predict the major organic product for the...

Question 13

Give two reasons why thioesters (such as acetyl-CoA) are used in biological systems instead of their analogous oxygen esters.

Accepted Answer

The answer of Give two reasons why thioesters (such as...

Question 14

The reaction shown is part of the fatty acid synthesis pathway. ACP is an abbreviation for acyl carrier protein, and you do not need to know its structure. Identify the reagent that could perform this transformation.

Accepted Answer

The presence of NADPH suggests that this is a reduction reaction, and NADPH is a known reducing agent in the fatty acid synthesis pathway. Choices B and C are not involved in this specific type of reaction.

Question 15

Predict the major organic product(s) for the reaction. If the reaction will not occur, write NR and explain why.

Accepted Answer

The answer of Predict the major organic product(s) for the...

Question 16

Draw a plausible curved-arrow mechanism to show the base-catalyzed hydrolysis of the phosphate triester, then draw the hydrolysis products.

Accepted Answer

The answer of Draw a plausible curved-arrow mechanism to show...

Question 17

DNA and RNA consist of phosphate diester backbone. With your knowledge of the reactivity of phosphate triesters and diesters towards hydrolysis, explain why a phosphate diester is an ideal functional group to connect monomer units in DNA and RNA.

Accepted Answer

The answer of DNA and RNA consist of phosphate diester...

Question 18

A phosphatase is

Accepted Answer

A phosphatase is an enzyme that hydrolyses a phosphate group from a molecule. This means it breaks the bond between the phosphate group and the molecule it is attached to, resulting in the release of the phosphate group. This is opposed to a kinase, which adds a phosphate group to a molecule.

Question 19

Predict the major organic products in the sequence:

Accepted Answer

The answer of Predict the major organic products in the...

Question 20

The structure of ATP is shown below. A nucleophile can react with which phosphorus atom?

Accepted Answer

The answer of The structure of ATP is shown below....

Quiz 25: The Chemistry of Thioesters, Phosphate Esters, and Phosphate Anhydrides