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    Chemistry of Peptides: A Coupling Reaction in Peptide Synthesis

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    Rakesh Kore
    This document discusses various coupling reagents used in peptide synthesis to form peptide bonds between amino acids. It describes common carbodiimide coupling reagents like DCC and DIC, uronium salts like HATU and HBTU, phosphonium salts like BOP and aminium salts. It also discusses fluoroformamidinium reagents and some organophosphorus reagents that are stable and crystalline for long term storage. The key application of these various reagents is in activating the carboxyl group of one amino acid so it can condense via amide bond formation with the amino group of another amino acid during chemical peptide synthesis.

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    Chemistry of Peptides: A Coupling Reaction in Peptide Synthesis

    Uploaded by

    Rakesh Kore
    471 views14 pages
    This document discusses various coupling reagents used in peptide synthesis to form peptide bonds between amino acids. It describes common carbodiimide coupling reagents like DCC and DIC, uronium salts like HATU and HBTU, phosphonium salts like BOP and aminium salts. It also discusses fluoroformamidinium reagents and some organophosphorus reagents that are stable and crystalline for long term storage. The key application of these various reagents is in activating the carboxyl group of one amino acid so it can condense via amide bond formation with the amino group of another amino acid during chemical peptide synthesis.

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    Presentation on Chemistry of peptides

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    chemistry of peptides

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    This document discusses various coupling reagents used in peptide synthesis to form peptide bonds between amino acids. It describes common carbodiimide coupling reagents like DCC and DIC, uronium salts like HATU and HBTU, phosphonium salts like BOP and aminium salts. It also discusses fluoroformamidinium reagents and some organophosphorus reagents that are stable and crystalline for long term storage. The key application of these various reagents is in activating the carboxyl group of one amino acid so it can condense via amide bond formation with the amino group of another amino acid during chemical peptide synthesis.

    Copyright:

    © All Rights Reserved
    Download as PPTX, PDF, TXT or read online from Scribd
    Download as pptx, pdf, or txt
    471 views14 pages

    Chemistry of Peptides: A Coupling Reaction in Peptide Synthesis

    Uploaded by

    Rakesh Kore
    This document discusses various coupling reagents used in peptide synthesis to form peptide bonds between amino acids. It describes common carbodiimide coupling reagents like DCC and DIC, uronium salts like HATU and HBTU, phosphonium salts like BOP and aminium salts. It also discusses fluoroformamidinium reagents and some organophosphorus reagents that are stable and crystalline for long term storage. The key application of these various reagents is in activating the carboxyl group of one amino acid so it can condense via amide bond formation with the amino group of another amino acid during chemical peptide synthesis.

    Copyright:

    © All Rights Reserved
    Download as PPTX, PDF, TXT or read online from Scribd
    Download as pptx, pdf, or txt
    of 14

    CHEMISTRY OF PEPTIDES : A

    COUPLING REACTION IN PEPTIDE


    SYNTHESIS

    Submitted by Rakesh kore


    M. Pharm pharmaceutical chemistry
    Ggu bilaspur
    CONTENTS

     INTRODUCTION
     PEPTIDE BOND FORMATION
     COUPLING REAGENTS
     CARBODIIMIDES
     URONIUM SALTS
     PHOSPHONIUM AND AMINIUM SALT
     FLUOROFORMAMIDINIUM COUPLING REAGENTS
     ORGANOPHOSPHORUS REAGENTS
    INTRODUCTION

     Peptide synthesis is the production of peptides, compounds where


    multiple amino acids are linked via amide bonds, also known as 
    peptide bonds.
     Peptides are chemically synthesized by the condensation reaction of the 
    carboxyl group of one amino acid to the amino group of another.
     Chemical peptide synthesis most commonly starts at the carboxyl end of
    the peptide (C-terminus), and proceeds toward the amino-terminus (N-
    terminus).
    PEPTIDE BOND FORMATION

     A key step in the peptide production process is the formation of the


    peptide bond. This requires the activation of a carboxylic acid, which is
    usually carried out using the peptide coupling reagents.
     If the activation of carboxylic acid is slow, the coupling reagents will be
    degraded and will no longer be able to activate the carboxyl function.
    COUPLING REAGENTS

     The coupling reaction in witch coupling reagents are used in the peptide
    bond formation in peptide synthesis .
    The coupling reagents are:

    I. Carbodiimides
    II. Uronium salts
    III. Phosphonium and aminium salts
    IV. Fluoroformanidimium coupling reagenst
    V. Organophosphorus reagents
    CARBODIIMIDES

     Carbodiimides Coupling: Carbodiimides react with carboxylic acids to


    form O-acylisourea mixed anhydrides which react directly with amines
    to give amides and a urea by-product.

    DCC- N,NO-dicyclohexylcarbodiimide
    DIC-Diisopropyl carbodiimide
    EDC- 1-13-(dimethylamino)propylj-3-ethylcarbodiimide
     Coupling:
    URONIUM SALTS

     A one-pot solution in which the active ester is prepared in situ as an


    intermediate and then reacts with the amine
     In solution, benzotriazole uronium species (O-form) are in
    equilibrium with the guanidinium species (N-form)

    HATU (1-[Bis(dimethylamino)methylene]-1H-1,2,3-triazolo[4,5-
    b]pyridinium 3-oxide hexafluorophosphate,
    HBTU (2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium
    hexafluorophosphate
    HCTU -1H-Benzotriazolium 1-[bis(dimethyl-amino)methylene]-5-
    chloro-hexafluorophosphate (1-),3-oxide
     Coupling:
    PHOSPHONIUM AND AMINIUM SALT

     The use of phosphonium salts as coupling reagents such as,


    (benzotriazol-1-yloxy)tris (dimethylamino) phosphonium
    hexafluorophosphate (BOP) and (benzotriazol-1yloxy)tris
    (pyrrolidino)phosphonium hexafluorophosphate (PyBOP).

     Phosphonium salts derived from HOAt, such as (7-azabenzotriazol-1-


    yloxy)tris(di methylamino)phosphonium hexafluorophosphate(AOP)
    and (7-azabenzotriazol-1yloxy)tris (pyrrolidino) phosphonium
    hexafluorophosphate(PYAOP) have also been prepared and are
    generally more efficient than BOP and PyBOP as coupling reagents.
    FLUOROFORMAMIDINIUM COUPLING REAGENTS

     Among the most reactive of the common coupling reagents are the
    preformed amino acid fluorides.
     The amidinium reagents are1,1,3,3-tetramethyl fluoroformamidinium
    hexafluorophosphate (TFFH), bis(tetramethylene) fluoroformamidinium
    hexafluorophosphate (BTFFH) and 1,3-dimethyl-2-fluoro-4,5-dihydro-
    1H imidazolium hexafluorophosphate (DFIH) these reagent used in
    peptide synthesis.
    ORGANOPHOSPHORUS REAGENTS

     The Organophosphorus reagents are diphenyl phosphorochloridate and


    These reagents are crystalline and stable for long-term storage.

    DECP-Diethyl chlorophosphiteDEPB-Diethyl(3-pyridyl)borane
    DEPC-Diethyl pyrocarbonate
    MPTA-a-Methoxy-a-Trifluoromethylphenylacetic acid
    MPTO-3-Dimethylphosphinothioyl-2(3H)-oxazolone
    Thank you

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