Aminoacids carboxyl group

We have prepared a wide series of Mo(VI)-grafted poly(amido amine) resins based on aminoacids with varying distances between the aminic and carboxylic groups. We have found that the catalytic activity of these resins is strongly dependent on that distance, maximum activity within this series being obtained when the resin supposedly co-ordinates to a Mo(VI)02 core in a quadridentate manner throught the use of two suitably located adjacent carboxylic functions. 

We note that, with the lone participation of a carboxyl group in the coordination, the coordination modes examined earlier for the complexes of carbonic acids (Sec. 2.2.5.4, formulae 276 283) are possible. Additionally, a mixed binding amongst ligands is observed in many complexes of aminoacids, for example chelates 277, 414, and 0,0 -bridge 279 [714],... 

The synthesis of conformationally constrained bicyclic and tricyclic compounds, obtained via 5-Exo-Trig iodocyclisation of polybenzylated sugars with an allylic substituent at the anomeric position, is described. The conformation of these molecules has been studied by n.O.e. experiments and Molecular Dynamics calculations. The introduction of an amino and a carboxylic group resulted in the formation of conformationally constrained bicyclic glyco-aminoacids that mimic protein turn conformation. 

The good fit of Dmt for the subsite might force the carboxyl group into close contact with the anion site of the fi receptor, explaining the high 8 selectivity of these compounds [72], Furthermore lipophilic aminoacids and water solubility imply a potential to transit the brain capillary endothelium. 

Another approach is the resolution of an enantiomeric mixture with a structurally similar resolving agent. It is the situation when one of the enantiomers of the racemic compwimd is transformed (with a minimal chemical transformation) into a reagent able to form diastereoisomeric salt with the initial racemic compound. It can be done if the aminoacid is N-acylated and one of the pure enantiomers is esterified, or if its carboxylic group is transformed into an amide, or changed with methyl group, respectively. 

Pyrroles have been functionalized at the 3 positions with a carboxyl group which in turn has been functionalized with aminoacids and enzymes by condensation (64). The polymers were produced electrochemically as films and tested for enzyme recognition. Specific recognition was found with carboxypeptidase A [305]. 

Under normal conditions in an aqueous solution the aminoacids are ionized, with one proton removed from the OH of the carboxyl group and transferred to... 

Besides numerous polyhedral boron hydride based a-aminoacids, a few compounds with carborane cage incorporated between amino and carboxylic groups were reported [107,108],... 

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