What is DCC coupling?

DCC (dicyclohexyl carbodiimide) is one of the most frequently used coupling agents, especially in organic synthesis applications. It has been used for peptide synthesis since 1955 (Sheehan and Hess, 1955) and continues to be a popular choice for creating peptide bonds (Barany and Merrifield, 1980).

What is the difference between Hatu and Hbtu?

O-(7-Azabenzotriazol-1-yl)-N,N,N’,N’-tetramethyluronium hexafluorophosphate (HATU) is similar to HBTU, but reacts faster with less epimerization during coupling. HATU is preferred to HBTU in most rapid coupling protocols. HATU is utilized in the same manner as HBTU.

What is the chemical use of DCC?

N,N′-Dicyclohexylcarbodiimide (DCC or DCCD) is an organic compound with the chemical formula (C6H11N)2C. It is a waxy white solid with a sweet odor. Its primary use is to couple amino acids during artificial peptide synthesis. The low melting point of this material allows it to be melted for easy handling.

Why does HOBt prevent racemization?

Adding HOBt, 6-Cl-HOBt or HOAt suppresses the racemization. Histidine and cysteine are especially prone to racemization. Protecting the pi imidazole nitrogen in the histidine side-chain with the methoxybenzyl group greatly reduces racemization.

Is DCC soluble in acetonitrile?

Solubility: DCC: highly sol dichloromethane, THF, acetonitrile, DMF. DMAP: sol dichloromethane, THF, acetonitrile, DMF, ethyl acetate.

Why is HOBt used?

Use in peptide synthesis HOBt is used to produce such activated esters. These esters are insoluble (like the N-hydroxysuccinimide esters) and react with amines at ambient temperature to give amides. HOBt is also used for the synthesis of amides from carboxylic acids aside from amino acids.

How can racemization be stopped?

How do you quench a reaction?

In a chemical quench setup (i.e., a quench flow), the reaction of interest is initiated by forcing the reactants together into a reaction loop using a rapid mixer, similarly to a stopped-flow instrument.

What is the purpose of DCC in peptide synthesis and how is it removed?

DCC, or dicyclohexylcarbodiimide, is a dehydrating agent that is normally used to synthesize proteins in a laboratory setting. It creates a good leaving group and removes a water molecule from the amino acids that are involved in the peptide bond formation.

What causes racemisation?

Racemization occurs when one pure form of an enantiomer is converted into equal proportion of both enantiomers, forming a racemate. When there are both equal numbers of dextrorotating and levorotating molecules, the net optical rotation of a racemate is zero.

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