Barbituric acid can be prepared from malonic ester and urea as shown. A complete, detailed mechanism for this reaction is to be provided. Concept introduction: In the basic solution, no strong acid should appear in the mechanism, hence, the proton transfer step occurs before the nucleophilic addition-elimination reaction. The nucleophilic addition-elimination mechanism has two steps. Step 1 is nucleophilic addition, in which a nucleophile attacks the electron poor carbonyl carbon. This forces the pair of electrons from the initial C=O bond onto the O atom which generates a negative charge on O. The product of that step is a tetrahedral intermediate, which, in Step 2, undergoes nucleophile elimination. A lone pair of electrons on the negatively charged O atom is used to regenerate the C=O double bond and the leaving group departs.

Question

Want to see the full answer?

Answer 1

Question

Chapter 20, Problem 20.41P

Interpretation Introduction

Interpretation:

Barbituric acid can be prepared from malonic ester and urea as shown. A complete, detailed mechanism for this reaction is to be provided.

Concept introduction:

In the basic solution, no strong acid should appear in the mechanism, hence, the proton transfer step occurs before the nucleophilic addition-elimination reaction. The nucleophilic addition-elimination mechanism has two steps. Step 1 is nucleophilic addition, in which a nucleophile attacks the electron poor carbonyl carbon. This forces the pair of electrons from the initial C=O bond onto the O atom which generates a negative charge on O. The product of that step is a tetrahedral intermediate, which, in Step 2, undergoes nucleophile elimination. A lone pair of electrons on the negatively charged O atom is used to regenerate the C=O double bond and the leaving group departs.

Expert Solution & Answer

Want to see the full answer?

Check out a sample textbook solution

See solution

Students have asked these similar questions

In reactions whose kinetic equation is v = k[A]m, the rate coefficient k is always positive. Is this correct?

If the concentration of A decreases exponentially with time, what is the rate equation? (A). -d[A] (B). dt d[A] = k[A] e-kt dt

Given the first-order reaction: aA → products. State its kinetic equation.

Answer 2

Question

Chapter 20, Problem 20.41P

Interpretation Introduction

Interpretation:

Barbituric acid can be prepared from malonic ester and urea as shown. A complete, detailed mechanism for this reaction is to be provided.

Concept introduction:

In the basic solution, no strong acid should appear in the mechanism, hence, the proton transfer step occurs before the nucleophilic addition-elimination reaction. The nucleophilic addition-elimination mechanism has two steps. Step 1 is nucleophilic addition, in which a nucleophile attacks the electron poor carbonyl carbon. This forces the pair of electrons from the initial C=O bond onto the O atom which generates a negative charge on O. The product of that step is a tetrahedral intermediate, which, in Step 2, undergoes nucleophile elimination. A lone pair of electrons on the negatively charged O atom is used to regenerate the C=O double bond and the leaving group departs.

Expert Solution & Answer

Want to see the full answer?

Check out a sample textbook solution

See solution

Answer 3

Question

Chapter 20, Problem 20.41P

Interpretation Introduction

Interpretation:

Barbituric acid can be prepared from malonic ester and urea as shown. A complete, detailed mechanism for this reaction is to be provided.

Concept introduction:

In the basic solution, no strong acid should appear in the mechanism, hence, the proton transfer step occurs before the nucleophilic addition-elimination reaction. The nucleophilic addition-elimination mechanism has two steps. Step 1 is nucleophilic addition, in which a nucleophile attacks the electron poor carbonyl carbon. This forces the pair of electrons from the initial C=O bond onto the O atom which generates a negative charge on O. The product of that step is a tetrahedral intermediate, which, in Step 2, undergoes nucleophile elimination. A lone pair of electrons on the negatively charged O atom is used to regenerate the C=O double bond and the leaving group departs.

Expert Solution & Answer

Want to see the full answer?

Check out a sample textbook solution

See solution

Answer 4

Question

Chapter 20, Problem 20.41P

Interpretation Introduction

Interpretation:

Barbituric acid can be prepared from malonic ester and urea as shown. A complete, detailed mechanism for this reaction is to be provided.

Concept introduction:

In the basic solution, no strong acid should appear in the mechanism, hence, the proton transfer step occurs before the nucleophilic addition-elimination reaction. The nucleophilic addition-elimination mechanism has two steps. Step 1 is nucleophilic addition, in which a nucleophile attacks the electron poor carbonyl carbon. This forces the pair of electrons from the initial C=O bond onto the O atom which generates a negative charge on O. The product of that step is a tetrahedral intermediate, which, in Step 2, undergoes nucleophile elimination. A lone pair of electrons on the negatively charged O atom is used to regenerate the C=O double bond and the leaving group departs.

Expert Solution & Answer

Want to see the full answer?

Check out a sample textbook solution

See solution

Answer 5

Chapter 20, Problem 20.41P

Interpretation Introduction

Interpretation:

Barbituric acid can be prepared from malonic ester and urea as shown. A complete, detailed mechanism for this reaction is to be provided.

Concept introduction:

In the basic solution, no strong acid should appear in the mechanism, hence, the proton transfer step occurs before the nucleophilic addition-elimination reaction. The nucleophilic addition-elimination mechanism has two steps. Step 1 is nucleophilic addition, in which a nucleophile attacks the electron poor carbonyl carbon. This forces the pair of electrons from the initial C=O bond onto the O atom which generates a negative charge on O. The product of that step is a tetrahedral intermediate, which, in Step 2, undergoes nucleophile elimination. A lone pair of electrons on the negatively charged O atom is used to regenerate the C=O double bond and the leaving group departs.

Answer 6

Chapter 20, Problem 20.41P

Interpretation Introduction

Interpretation:

Barbituric acid can be prepared from malonic ester and urea as shown. A complete, detailed mechanism for this reaction is to be provided.

Concept introduction:

In the basic solution, no strong acid should appear in the mechanism, hence, the proton transfer step occurs before the nucleophilic addition-elimination reaction. The nucleophilic addition-elimination mechanism has two steps. Step 1 is nucleophilic addition, in which a nucleophile attacks the electron poor carbonyl carbon. This forces the pair of electrons from the initial C=O bond onto the O atom which generates a negative charge on O. The product of that step is a tetrahedral intermediate, which, in Step 2, undergoes nucleophile elimination. A lone pair of electrons on the negatively charged O atom is used to regenerate the C=O double bond and the leaving group departs.

Answer 7

Chapter 20, Problem 20.41P

Interpretation Introduction

Interpretation:

Barbituric acid can be prepared from malonic ester and urea as shown. A complete, detailed mechanism for this reaction is to be provided.

Concept introduction:

In the basic solution, no strong acid should appear in the mechanism, hence, the proton transfer step occurs before the nucleophilic addition-elimination reaction. The nucleophilic addition-elimination mechanism has two steps. Step 1 is nucleophilic addition, in which a nucleophile attacks the electron poor carbonyl carbon. This forces the pair of electrons from the initial C=O bond onto the O atom which generates a negative charge on O. The product of that step is a tetrahedral intermediate, which, in Step 2, undergoes nucleophile elimination. A lone pair of electrons on the negatively charged O atom is used to regenerate the C=O double bond and the leaving group departs.

Answer 8

Expert Solution & Answer

Answer 9

Expert Solution & Answer

Answer 10

Want to see the full answer?

Check out a sample textbook solution

See solution

Answer 11

Ch. 20 - Prob. 20.1P Ch. 20 - Prob. 20.2P Ch. 20 - Prob. 20.3P Ch. 20 - Prob. 20.4P Ch. 20 - Prob. 20.5P Ch. 20 - Prob. 20.6P Ch. 20 - Prob. 20.7P Ch. 20 - Prob. 20.8P Ch. 20 - Prob. 20.9P Ch. 20 - Prob. 20.10P

Solution Summary: The author explains that barbituric acid can be prepared from malonic ester and urea. The nucleophilic addition-elimination reaction has two steps.

Concept explainers

Videos

Want to see the full answer?

Chapter 20 Solutions