Primary amines complexes with Schiff bases

The reaction of 2,2 -dithiodibenzaldehyde with Ni11 complexes containing coordinated primary amines results in Schiff base condensation and cleavage of the disulfide bond to form a chelating... 

Monoamine oxidase catalyzes the deamination of primary amines and some secondary amines, with some notable exceptions. Aromatic amines with unsubstituted a-carbon atoms are preferred, but aromatic substituents influence the binding of these substrates. For example, m-iodobenzylamine is a good substrate, whereas the o-iodo analog is an inhibitor. The mechanism of deamination is as follows hydrolysis of the Schiff base that results from loss of a hydride ion on an a-proton yields an aldehyde, which is then normally oxidized to the carboxylic acid. Aromatic substrates are probably preferred because they can form a charge-transfer complex with the FAD at the active site, properly... 

If the interconversion between the two enantiomeric substrates is rapid and the product is relatively stable, and thus irreversibly formed, then the magnitude of the rate constants, kR and ks, will dictate which product isomer is formed (Figure 19.3). The racemization reaction is most often catalyzed by metal ion complexes containing Ru or Pd, but silica, ion-exchange resins, or enzymes can also be used. The addition of aldehydes can also be used to facilitate the racemization process through the formation of a Schiff base with primary amines and amino acids. 

The decarboxylation has also long been known to be catalyzed by primary amines117. According to this pathway, the keto group forms a covalent complex (Schiff base) with the primary amine. The imine formed, or its iminium form is decarboxylated to an enamine, that in turn is hydrolyzed to the ketone (Scheme 11). 

Primary amines (such as the e-amino group of lysine) react readily with aldehydes, often forming Schiff bases which can be stabilized by reduction with NaBH4. Such a reaction forms the basis of the widespread use of pyridoxal phosphate to modify chemically the lysine residues of proteins. In recent years, in order to increase the specificity of labeling, aldehydes have been incorporated into more complex compounds which mimic the structures of the substrate or cofactor of the enzyme. 

A review describes the asymmetric epoxidation of allylic alcohols,369 another the role of metal oporphyrins in oxidation reactions.370 jhe TiiOPrMi, catalysed self-epoxidation of allylic peroxides proceeds via an intermolecular mechanism.371 Racemic allyl alcohols can be resolved by asymmetric epoxidation (eq.35).372 a Pd(II)/Mn02/benzoquinone system catalyses the oxidative ring-closure of 1,5-hexadienes (eq.36).373 propenyl phenols are oxidatively degraded to aryl aldehydes and MeCHO in the presence of Co Schiff-base catalysts.374 An Oppenauer-type oxidation with Cp2ZrH2/cyclohexanone converts primary alcohols selectively into aldehydes.375 co macrocycles catalyse the oxidation of aryl liydrazones to diazo compounds in high yields.376 similar Co complexes under CO oxidise primary amines to azo compounds.377 Arene Os complexes in the presence of base convert aldehydes and water slowly into carboxylic acids and H2.378... 

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