Carbodiimide coupling

Organic synthesis [OS 15] Dipeptide synthesis by carbodiimide coupling using... 

Boc-D-alanine and (S)-a-methylbenzylamine react to give the corresponding dipep tide via an EDCI [3-ethyl-l-(3-dimethylaminopropyl)-carbodiimid] coupling [86], control experiment, Boc-t-alanine and (S)-a-methylbenzylamine also reacted. 

Carbodiimide coupling to carboxylate-containing QDs usually involves the use of EDC in a single-step or two-step process to form an amide bond. If a one-step reaction is done, the QD is activated with EDC in the presence of an amine-containing molecule, such as a protein. Many protocols use this method, but it can result in protein polymerization in addition to coupling, because proteins contain both carboxylates and amines. A two-step protocol results in better control of the reaction (Figure 9.61). In the first step, EDC is used in the presence of sulfo-NHS to activate the carboxylates on the particles to intermediate sulfo-NHS esters. After a quick separation step to remove excess reactants, the activated QDs are added to the protein solution to be coupled. This then results in amide bond formation without polymerization of the protein in solution. See Chapter 3, Section 1 and Chapter 14, Section 1 for additional information on this process. 

Figure 22.30 An iodoacetamide derivative of PE containing an extended spacer arm can be constructed through a carbodiimide coupling of iodoacetic acid to PE, followed by reaction with 2-mercaptoethylamine, and finally another reaction with iodoacetate.

Add the aldehyde-derivatized alkaline phosphatase to 8 nmol of a 5 -hydrazide oligonucleotide preparation made according to Section 2.1 (this chapter) using a carbodiimide coupling protocol. 

H Hagenmeier, H Frank. Increased coupling yields in solid phase peptide synthesis with a modified carbodiimide coupling procedure. Hoppe-Seyler s Z Physiol Chem 353, 1973, 1972. 

Supported reagents have found application in many areas of synthesis including the construction of small peptides, the traditional foundation stone of solid phase synthesis. For example a recent paper describes the preparation of dipeptide p-nitroanilide and phosphonate libraries by supported carbodiimide coupling and scavenger purification (Scheme 2.52) [79]. 

Carbodiimide Coupling of Peptides to Carrier Proteins with 1 -Ethyl-3-(3-Dimethylaminopropyl)-Carbodiimide (EDAC, EDO... 

The carbodiimide coupling of N-methylphenylglycinc with benzylamine gives a product whose 1II NMR is shown in Figure 11.29. The expected product is the amino amide. The NMR spectrum shows first that both reactants are incorporated in file product. 

Conjugation via Carbodiimide Coupling to Phosphatidylethanolamine Lipid Derivatives... 

For binding protein and human serum albumin to carboxylic acid-terminated magnetic particles was used carbodiimide coupling method. 

The coupling chemistries that have been widely used in organic chemistry for producing chemical bonds have been applied to form irreversible and stable nanoparticle arrays on surfaces. Eychmriller et al. used the carbodiimide coupling chemistry to covalently assemble carboxylate-functionalized CdTe nanocrystals (NCs) onto amino-terminated glass surfaces, which resulted in densely covered nanoparticle films.14 The same principle was also applied to coat Si02 microparticles by CdTe NCs. 

Andres and coworkers demonstrated the iCP of densely packed alkanethiolate-functionalized Au nanoparticle arrays in monolayer and multilayer structures.81,82 Dense and hexagonally packed monolayers of nanoparticles were first assembled on a water surface. By using the Langmuir-Schafer technique, the Au nanoparticle monolayer was transferred to a PDMS stamp, and printed onto a substrate. Multilayers were prepared by repeating the printing process in an LbL scheme, in which subsequent particle layers may be made up of the same or different types of particles. Similarly, the assembly of irregular, densely packed monolayers of polystyrene nanoparticles on iCP substrates via carbodiimide coupling was reported.83 The conformal contact of the carbodiimide-functionalized polystyrene particles resulted in the covalent attachment of the nanoparticles at a carboxylate-functionalized surface. 

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