Couplingreagents inpeptidesynthesis BOP peptide coupling, referring to the use of the BOP reagent (benzotriazol-1-yloxy)tris(dimethylamino)phosphonium hexafluorophosphate, is a critical method for forming peptide bonds in modern organic synthesis. As a widely recognized peptide coupling reagent, BOP facilitates the efficient formation of amide bonds between amino acids and peptides, playing a crucial role in both solid-phase and solution-phase peptide synthesis. Its ability to provide excellent coupling behavior and good solubility in common solvents makes it a valuable tool for researchers aiming to construct complex peptide sequences.
The fundamental process of BOP peptide coupling involves the activation of a carboxylic acid group on one amino acid (or peptide) to create a reactive intermediate. This activated species is then susceptible to nucleophilic attack by the amine group of another amino acid or peptide, resulting in the formation of a new peptide bond and the release of the BOP reagent's activating moiety. This mechanism is central to building longer peptide chains, a process that underpins significant advancements in drug discovery, biochemistry, and materials science.
The BOP reagent, chemically known as (Benzotriazol-1-yloxy)tris(dimethylamino)phosphonium hexafluorophosphate, functions by forming an activated ester or an acyloxyphosphonium salt intermediate. This intermediate is highly reactive and readily undergoes nucleophilic attack by the amine component. The overall reaction is typically carried out in organic solvents such as N,N-dimethylformamide (DMF) or N-methylpyrrolidone (NMP), which facilitate good solubility and reaction kinetics.
The mechanism of BOP-mediated coupling is often depicted as involving the formation of an O-acylisourea intermediate or, more precisely, an active esterBOP Reagent vs. PyBOP for Peptide Synthesis. This activated species is then attacked by the free amine of the coupling partner, leading to the formation of the desired peptide bond. While effective, it's important to note that the use of BOP can generate hexamethylphosphoramide (HMPA) as a by-product, which is a known carcinogen. This has led to the development of alternative reagents.
BOP peptide coupling offers several distinct advantages that have contributed to its widespread use作者：M Forest·1990·被引用次数：50—Thecouplingreactions were carried out in N,N-dimethylformamide or N-methylpyrrolidone. These solvents allowed the incorporation of the N-terminal pyroglutamic .... It is renowned for its efficiency in forming peptide bonds, often proceeding rapidly and to a high degree of completion.Applications of BOP reagent in solid phase synthesis ... This is particularly beneficial in solid-phase peptide synthesis (SPPS), where rapid and complete coupling reactions are essential for maximizing yields and minimizing side products. BOP couplings using the solid-phase procedure have been shown to proceed more rapidly and to a greater extent of completion compared to some older methods.
Furthermore, BOP reagent is effective in suppressing enantiomerization during the coupling process, a crucial factor for maintaining the stereochemical integrity of the synthesized peptides. This is particularly important when dealing with sensitive amino acids or when synthesizing peptides with specific conformational requirements作者：IA Rivero·1995·被引用次数：20—The peptide couplingis often carried out in DMF in the presence of BOPand the reaction goes to completion in 2 h 1,2,3,4. Two modified inexpensive synthetic .... The reagent's good solubility also contributes to its versatility, allowing for its application in both solution and solid-phase methodologies.
Despite its efficacy, the generation of carcinogenic by-products like HMPA has prompted the development and adoption of alternative peptide coupling reagentsThe Chemistry of Coupling: Understanding BOP Reagent .... Among the most prominent alternatives is PyBOP® (benzotriazol-1-yloxy)tripyrrolidinophosphonium hexafluorophosphate), an analog of BOP where the dimethylamino groups are replaced with pyrrolidino groups.BOP REAGENT| SYNTHETIC COUPLING REAGENT.pptx PyBOP exhibits equivalent properties in peptide bond formation and is often preferred due to its reduced toxicity profile. Other related reagents, such as BOP-Cl (Bis(2-oxo-3-oxazolidinyl)phosphorodiamidic chloride), are also employed as coupling agents for amide and ester formation, offering different reactivity profiles and by-product considerations.
When selecting a coupling reagent, factors such as reaction efficiency, yield, the potential for side reactions, the cost of the reagent, and importantly, the toxicity of by-products, must be carefully weighedBOP-Cl is a phosphoric acid derivative used as a coupling reagentfor amide and ester formation. BOP-Cl is effective in the acylation of N-methylated amino .... While BOP remains a potent tool, awareness of its limitations and the availability of safer, equally effective alternatives like PyBOP and HBTU (which also generate OBt esters) is essential for modern peptide synthesis.Peptide Coupling Reagents & Additives: A Guide - Bachem The choice of coupling reagent directly impacts the success of the synthetic strategy, influencing the purity, yield, and stereochemical fidelity of the final peptide product.
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