Amidine binding site

The usefulness of these novel amidine binding site monomers in molecular imprinting was demonstrated by their application in the preparation of polymers that were imprinted with optically active A -(4-carboxybenzoyl)-phenylglycine (15) the resulting materials could discriminate between the enantiomers of the template molecule with a values of up to 2.8 [12]. 

Pinacolone, o-(diphenylphosphino)benzoyl-coordination chemistry, 401 Piperidine, IV-hydroxy-metal complexes, 797 pA a values azole ligands, 77 Plant roots amino acids, 962 carboxylic acids, 962 Plastocyanin copper binding site, 557 copper(II) complexes, 772 copper(II) site in, 770 Platinum, dichlorobis(benzonitrile)-IR spectrum, 264 Platinum, cis-dichlorodianunine-antitumor activity, 34, 979 Platinum, ethylenebis(triphenylphosphine)-reactions with 5,6-dimethyl-2,l,3-benzothiadiazole, 194 Platinum blue formation, 265 Platinum complexes acetylacetone reactions, 380 amides, 491 amidines... 

Optically active phosphine monoester 69 was prepared as a stable transition state analogue of the hydrolysis of 70, and used as a template (Scheme 13.17) [52], When heated in the presence of amidine 72, methyl methacrylate, ethylene glycol dimethacrylate and AIBN, polymerization took place and offered the polymer 73, in which the template 69 is attached to the binding sites by a combination of hydrogen bonds and electrostatic interactions. After washing in the presence of MeOH and aqueous NaOH, the template was removed from the cavity, thus leading to a catalytically active MIP. 

Wulff, G. Schonfeld, R. Polymerizable amidines— adhesion mediators and binding sites for molecular imprinting. Adv. Mater. 1998,10, 957-959. 

The amidine group is a very efficient binding site able to form multiple hydrogen bonds as well as electrostatic interactions. It strongly interacts with oxyanions, such... 

The amidine group can act as a binding site or a catalytic site at the same time. As will be described more in detail in Chapter 21, stable transition-state analogues for the basic ester hydrolysis like 14 or 16 can be used as bis-amidinium salts to get efficient enzyme mimics for the ester hydrolysis of 15 [29] and 17. In case of 17, even enantioselective reactions are possible [60]. 

In amidines, the push-pull effect increases the electron density on the imino nitrogen at the expense of the amino nitrogen. In the complexes of formamidine with Li, Na, Mg and A1 cations, the structures in which M+ bridges both the amino and imino nitrogen atoms are tree minima on the PES but lie about 20 kJ mol above the imino monodentate complex [64], In the complex of Cu with guanidine, the imino nitrogen is also the preferred binding site [65],... 

The charges of the molecule are important for binding. When the amidine group accepts a proton and becomes an amidinium ion, noformycin and amidinomycin become biscationic and bind strongly to AT sequences. These two molecules have large pKa values at both basic sites and, as such, are biscationic at physiological pH. 

New approaches to design inhibitors of Factor Xa as potential anticoagulants have been reviewed (173), and important type III mimetics have been described (Fig. 15.42). All inhibitors contain amidine or basic groups that bind in the enzyme s site none of the inhibitors contains a classical electrophilic center of the type employed in TSA inhibitors (174-180). 

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