Coupling, aldehyde groups

Hydroformylated nitrile rubbers might have potential as binders for coupling with other rubbers due to the presence of polar aldehyde group. This might also open up the still greater potential of NBR containing saturated backbone in composite materials [1]. 

Gopner A, SL Daniel, HE Drake (1994) Acetogenesis coupled to the oxidation of aromatic aldehyde groups. Arch Microbiol 161 126-131. 

The three fragments were then coupled. The C(16)—C(17) bond was established by addition of the lithium enolate of the aryl ester in the C(9)—C(16) fragment with the aldehyde group of the C(17)-C(24) fragment. The stereochemistry is consistent with the cyclic aldol addition TS. The adduct was immediately reduced to the diol 14 by LiAlH4. 

Figure 5.35 ABH reacts with aldehyde-containing compounds through its hydrazide end to form hydrazone linkages. Glycoconjugates may be labeled by this reaction after oxidation with sodium periodate to form aldehyde groups. Subsequent photoactivation with UV light causes transformation of the phenyl azide to a nitrene. The nitrene undergoes rapid ring expansion to a dehydroazepine that can couple to nucleophiles, such as amines.

The amines on the surface of PAMAM-type and other amine-containing dendrimers may be used to couple to aldehyde groups in other molecules, including those formed after periodate... 

Figure 7.11 Oxidation of glycoproteins with periodate, such as glycosylated antibodies, results in the formation of aldehyde groups that can be used for conjugation to dendrimers containing amine groups. Reductive amination with sodium cyanoborohydride results in coupling via secondary (or tertiary) amine bonds.

Enzymes that are glycosylated (i.e., HRP and GO) may be oxidized according to the following method to produce aldehyde groups for reductive amination coupling to an antibody molecule. 

For this reaction, soluble monomers are needed, e.g. a mixture of N AT-methylene bisacrylamide as crosslinker, methacrylamide as an inert comonomer, methacrylic acid as ionic comonomer for stabilization [309] and methacryl ami-do-AT-acetaldehyde-dimethylacetal as functional comonomer. The coupling with proteins is only possible if the free aldehyde groups are accessible, i.e. if they are not located in the interior of the microgel. This condition can only be fulfilled by a careful choice of the comonomer composition in the reaction mixture [291]. 

Fig.1 Schematic illustration of the immobilization of penicillin G acylase on glutamate-pillared LDHs. Reaction of the primary amino groups of the intercalated glutamate ions with glutaraldehyde through Schiff s base formation is followed by covalent coupling of the residual aldehyde groups with the free amino groups of the enzyme...

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