Log out Go to App
Go to App

Learning Materials

Features

Discover

Chapter 24: Q24P. (page 1287)

Question. Propose a mechanism for the coupling of acetic acid and aniline using DCC as a coupling agent.

Short Answer

Expert verified

Representation of DCC as c-Hx

Mechanism for the coupling of acetic acid aniline

Step by step solution

01

Step1: Introduction to DCC

DCC or N,N’-Dicyclohexylcarbodiimide is used in the coupling reactions of amino acids during peptide synthesis. It has a low melting point and can be handled easily. Often, in reactions, we use the abbreviation ‘c-Hx’ to stand for cyclohexyl in DCC.

Representation of DCC as c-Hx

02

Mechanism for the reaction

The nitrogen of aniline firstly abstracts hydrogen from acetic acid-forming acetate ion and anilinium ion. Then, the oxygen of the acetate ion acts as a nucleophile and attacks thecarbon center of DCC, which is an electrophile. DCC thereby activatesthe carboxyl group,converting it into an excellent leaving group. Further, a reaction with another molecule of aniline occurs inthis activated carboxyl group, and lastly, the leaving group leaves, which is resonance-stabilized, and the final product is formed.

Mechanism for the coupling of acetic acid aniline

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Start your free trial

Over 30 million students worldwide already upgrade their learning with Vaia!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

The Sanger method for N-terminus determination is a less common alternative to the Edman degradation. In the Sanger method, the peptide is treated with the Sanger reagent, 2,4-dinitrofluorobenzene, and then hydrolyzed by reaction with 6 M aqueous HCl. The N-terminal amino acid is recovered as its 2,4-dinitrophenyl derivative and identified.

(a)Propose a mechanism for the reaction of the N terminus of the peptide with 2,4-dinitrofluorobenzene.

(b) Explain why the Edman degradation is usually preferred over the Sanger method.

Complete hydrolysis of an unknown basic decapeptide gives Gly, Ala, Leu, Ile, Phe, Tyr, Glu, Arg, Lys, and Ser. Terminal residue analysis shows that the N terminus is Ala, and the C terminus is Ile. Incubation of the decapeptide with chymotrypsin gives two tripeptides, A and B, and a tetrapeptide, C. Amino acid analysis shows that peptide A contains Gly, Glu, Tyr, and; peptide B contains Ala, Phe, and Lys; and peptide C contains Leu, Ile, Ser, and Arg.Terminal residue analysis gives the following results.

Incubation of the decapeptide with trypsin gives a dipeptide D, a pentapeptide E, and a tripeptide F. Terminal residue analysis of F shows that the N terminus is Ser and the C terminus is Ile. Propose a structure for the decapeptide and for fragments A through F.

Show how solid-phase peptide synthesis would be used to make Ile-Gly-Asn.

Show the third and fourth steps in the sequencing of oxytocin. Use figure 24-14 as a guide.

Suggest how you would separate the free L-amino acid from its acylated D enantiomer in Figure 24-5.

See all solutions

Recommended explanations on Chemistry Textbooks

Nuclear Chemistry

Read Explanation

Inorganic Chemistry

Read Explanation

The Earths Atmosphere

Read Explanation

Making Measurements

Read Explanation

Chemistry Branches

Read Explanation

Ionic and Molecular Compounds

Read Explanation
View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.

Sign-up for free