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Chemistry of Peptide Synthesis

ISBN-10:1-57444454-9
ISBN-13:978-1-57444454-4

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Description

General descriptionThis is an overview of how peptides are synthesized and what techniques are likely to generate the most desirable reactions. The author first outlines the fundamentals of peptide synthesis, focusing on the intermediates in aminolysis reactions. It then builds into discussions of the applicability of coupling reactions, stereomutation, methods of deprotection, solid-phase synthesis, side-chain protection and side reactions, and amplification on coupling methods. It clarifies the differences between oxazolones from amino-acid derivatives and segments and the implications of their formation on the chiral integrity of products. The author offers a critical analysis of the mechanisms of coupling reactions and the desirability of preactivation. The text explains hindrance and the nucleophilicity of tertiary amines and rationalizes their use. It also explores mechanisms of acidolysis and the dual role of nucleophiles as reactants and scavengers.

Properties

publication infoN. Benoiton, CRC Press, 2005, 304 pp., hard cover

Table Of Contents

Table of ContentsPARTIAL

FUNDAMENTALS OF PEPTIDE SYNTHESIS
Chemical and Stereochemical Nature of Amino Acids
Ionic Nature of Amino Acids
Charged Groups in Peptides at Neutral pH
Side-Chain Effects in Other Amino Acids
General Approach to Protection and Amide-Bond Formation
N-Acyl and Urethane-Forming N-Substituents

METHODS FOR THE FORMATION OF PEPTIDE BONDS
Coupling Reagents and Methods and Activated Forms
Peptide-Bond Formation from Carbodiimide-Mediated Reactions of N-Alkoxycarbonylamino Acids
Factors Affecting the Course of Events in Carbodiimide-Mediated Reactions of N-Alkoxycarbonylamino Acids
Intermediates and Their Fate in Carbodiimide-Mediated Reactions of N-Alkoxycarbonylamino Acids
Peptide-Bond Formation from Preformed Symmetrical Anhydrides of N-Alkoxycarbonylamino Acids
Peptide-Bond Formation from Mixed Anhydrides of N-Alkoxycarbonylamino Acids

PROTECTORS AND METHODS OF DEPROTECTION
The Nature and Properties Desired of Protected Amino Acids
Alcohols from which Protectors Derive and Their Abbreviated Designations
Deprotection by Reduction: Hydrogenolysis
Deprotection by Reduction: Metal-Mediated Reactions
Deprotection by Acidolysis: Benzyl-Based Protectors
Deprotection by Acidolysis:tert-Butyl-Based Protectors

CHIRALITY IN PEPTIDE SYNTHESIS
Mechanisms of Stereomutation: Acid-Catalyzed Enolization
Mechanisms of Stereomutation: Base-Catalyzed Enolization
Enantiomerization and Its Avoidance during Couplings of N-Alkoxycarbonyl-L-Histidine
Mechanisms of Stereomutation: Base-Catalyzed Enolization of Oxazolones Formed from Activated Peptides
Mechanisms of Stereomutation: Base-Induced Enolization of Oxazolones Formed from Activated N-Alkoxycarbonylamino Acids
Stereomutation and Asymmetric Induction

SOLID-PHASE SYNTHESIS
The Idea of Solid-Phase Synthesis
Solid-Phase Synthesis as Developed by Merrifield
Vessels and Equipment for Solid-Phase Synthesis
A Typical Protocol for Solid-Phase Synthesis
Features and Requirements for Solid-Phase Synthesis
Options and Considerations for Solid-Phase Synthesis

REACTIVITY, PROTECTION, AND SIDE REACTIONS
Protection Strategies and the Implications Thereof
Constitutional Factors Affecting the Reactivity of Functional Groups
Constitutional Factors Affecting the Stability of Protectors
The e-Amino Group of Lysine
The Hydroxyl Groups of Serine and Threonine
Acid-Induced O-Acylation of Side-Chain Hydroxyls and the O-to-N Acyl Shift

VENTILATION OF ACTIVATED FORMS AND COUPLING METHODS
Notes on Carbodiimides and Their Use
Cupric Ion as an Additive that Eliminates Epimerization in Carbodiimide-Mediated Reactions
Mixed Anhydrides: Properties and Their Use
Secondary Reactions of Mixed Anhydrides: Urethane Formation
Decomposition of Mixed Anhydrides: 2-Alkoxy-5(4H)-Oxazolone Formation and Disproportionation
Activated Esters: Reactivity

MISCELLANEOUS
Enantiomerization of Activated N-Alkoxycarbonylamino Acids and Esterified Cysteine Residues in the Presence of Base
Options for Preparing N-Alkoxycarbonylamino Acid Amides and 4-Nitroanilides
Options for Preparing Peptide Amides
Aggregation during Peptide-Chain Elongation and Solvents for its Minimization
Alkylation of Peptide Bonds to Decrease Aggregation: 2-Hydroxybenzyl Protectors

APPENDICES