Coupling agents, synthesis using

Iodosobenzene diacetate is used as a reagent for the preparation of glycol diacetates from olefins,9 for the oxidation of aromatic amines to corresponding azo compounds,10 for the ring acetylation of N-arylacetamides,11 for oxidation of some phenols to phenyl ethers,12 and as a coupling agent in the preparation of iodonium salts.13 Its hydrolysis to iodosobenzene constitutes the best synthesis of that compound.14... 

A-Acetylimidazole was found to be a very efficient terminating (capping) agent in the solid-phase synthesis of peptides.t40],[41] A terminating agent is used to block any N-terminal amino groups that have not reacted in the coupling steps.[40]... 

In ref. [123], 1-triisopropylbenzenesulfonyl- or mesitylenesulfonyl-5-(pyridine-2-yl)-tetrazole (VIII) was successfully used as a coupling agent for the synthesis of protected di- and trinucleotides. In comparison with the sulfonic acid tetrazolides these are able to achieve a stereoselective synthesis of dinucleoside monophosphate aryl esters. 311 1241... 

Instead of the isolated arylsulfonic acid azolides, mixtures of arylsulfonic acid chlorides and azoles have also been used for phosphorylation on a nucleoside 5 -OH or as coupling agents in the synthesis of oligodeoxyribonucleotides. 94 133 1371... 

In 2001, De Luca and GiacomeUi " reported a new simple and high-yielding one-flask synthesis of Weinreb amides from carboxylic acids and A-protected amino acids that uses different 1,3,5-triazine derivatives (such as 236) as the coupling agents (Scheme 104). The method allows the preparation of Weinreb amides 237 and hydroxamates as O-benzyl and 0-silyl hydroxamates that can be easily transformed into hydroxamic acids. 

Coupling reactions allow the synthesis of star (multiarmed) polymers (Sec. 3-15b-5) by using a multifunctional coupling agent such as SiCLj, CH3SiCl3, (C1CH2)4, and 1,2,4,5-tetra-chloromethylbenzene [Alward et al., 1986 Hadjichristidis et al., 2001 Lutz and Rempp, 1988 Quirk et al., 1999 Remp et al., 1988] for example... 

A similar cross-coupling reaction was used for the synthesis of the immunosuppressive agent FTY720 (Scheme 66) . 

The use of alkylchlorosilanes as coupling agents for the synthesis of stable, hydrophobic, surfactant extracted MCM-48/VO, catalysts. 

The synthesis of the Saa-peptide conjugates in solution follows standard solution-phase synthesis using, for example, IIDQt117 or EDC as the coupling agent. The reaction is checked by TLC (ninhydrin and/or 10% H2S04 in MeOH dip). The product is usually purified by flash chromatography. 

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