Calix[4]arenes with perfluorinated alcoholic functions at the upper rim: a new class of neutral anion receptors

Pelizzi, Nicola; Casnati, Alessandro; Ungaro, Rocco

doi:10.1039/a806837b

Cited by 33 publications

(11 citation statements)

References 19 publications

(14 reference statements)

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“…The enantioselective recognition of chiral carboxylates is also an important goal, because several pharmaceutical compounds possess this functional group. Efficient synthetic receptors for carboxylate anion recognition have been obtained by incorporating in more complex structures charged guanidinium, amidinium, or ammonium groups (2) and neutral H-bonding donor groups such as (thio) ureas (7), pyrroles (8), activated amides (9,10), and trifluoromethyl alcohols (11). Only a few examples are known where natural amino acids are used as binding units in biomimetic receptors for carboxylate recognition (12).…”

mentioning

confidence: 99%

Biomimetic macrocyclic receptors for carboxylate anion recognition based on C -linked peptidocalix[4]arenes

Sansone¹,

Baldini²,

Casnati³

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

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Two neutral macrobicyclic anion receptors 4 and 6, containing a calix[4]arene in the cone conformation, two L-alanine units, and a 2,6-diacylpyridine or a phthaloyl bridge, are described. The x-ray crystal structure of the acetone complexes of the pyridine containing macrocycle 6 shows the four amide NH groups to be in close proximity to the chiral pocket delimited by the pyridine and one aromatic nucleus of the calix[4]arene. This conformation is also the most stable in acetone-d6 solution, as proven by one-and twodimensional NMR spectral measurements. Electrospray ionization-MS and 1 H NMR experiments reveal that the two ligands strongly bind carboxylate anions in acetone solution. H-bonding interactions between the carboxylate anions and the amide NH groups, together with ͞ stacking, are invoked to explain the efficiency and the selectivity of these anion receptors.

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mentioning

confidence: 99%

Biomimetic macrocyclic receptors for carboxylate anion recognition based on C -linked peptidocalix[4]arenes

Sansone¹,

Baldini²,

Casnati³

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

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“…If we compare the binding properties of receptor 3a toward acetate anion with other difunctionalized calix [4]arene receptors we find that trifluoroethanol is less efficient than other anion binding groups such as urea [15,16], sulfonamide [53] or activated carboxyamides [54][55][56]. However, a comparison with receptors which contain simple alcoholic functions, which show no binding ability towards acetate anion [31], points out the importance of the electrowithdrawing groups CF3 in enhancing the H bonding ability of the OH groups. The modest binding constants and the "normal" acetate > benzoate selectivity observed for ligand 3a suggests that the apolar cavity of the calix [4]arene does not play an important role in anion binding in contrast to that observed with other receptors [16,55,57,58].…”

Section: Anion Binding Propertiesmentioning

confidence: 93%

“…Calix [4]arene diamide (29) [45] was selectively formylated on the positions para to the phenolic hydroxy groups. The tetra- (30) or diformyl (31) derivatives were subsequently alkylated with N,N-diethyl-a-cloroacetamide to give the tetramides 11 and 9 in very good yields. Trifluoromethylation of these compounds gave the trifluoromethyl alcohols 12 and 10a,b rather efficiently (68 cind 52% yields, respectively).…”

Section: Synthesis Of the Ligandsmentioning

confidence: 99%

“…Moreover, Pirkle et al used chiral fluoroalcohols as chiral solvating agents and were able to determine the enantiomeric compositions of chiral Lewis bases [30]. Surprisingly enough, so far nobody, except us [31,32], has exploited the fluoroalcoholic function as binding site in the design of more complex receptors for anions anci polar organic molecules [25,26]. We report herein a general and mild strategy to introduce one, two or four trifluoroethanol functions at the upper rim of ' caUx [4]arene derivatives, together with their binding properties towards anions and ion pairs.…”

Section: Introductionmentioning

confidence: 99%

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Calix[4]arene Anion Receptors Bearing 2,2,2-trifluoroethanol Groups at TheUpperRim

Casnati

Sartori

Pirondini

et al. 2006

Supramolecular Chemistry

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Several di-and tetrafunctionalized anion receptors have been synthesized by attaching 2,2,2-trifluoroethanol binding groups at the upper rim of cone calix[4]arenes using two different synthetic procedures. The best results were obtained hy treating calix[4]arene formyl derivatives with trifluoromelhyitrimethylsilane and tetra butyl ammonium fluoride in dry THF. The bistrifluoroethanol calix[4]arene receptors are able to bind anions showing selectivity for carboxylates and dihydrogenphosphate but at a lower efficiency compared to analogous receptors hearing urea, sulfonamide or activated amide binding groups. The conformational properties of the free ligands and their acelate complexes have heen investigated hy Dynamic 'H NMR, Molecular Modeling and in one case, by X-ray crystallography. CaHx[4|arenes bearing cation coordinating groups at the lower rim and 2,2,2-trifluoroethanol moieties at the upper rim behave as ditopic receptors, since they bind simultaneously cation and anion and extracts ion pairs in organic media. In one case evidence was obtained that coordination of sodium metal ion at the lower rim enhances the binding of acetate anion at the upper rim (positive allosteric effect).

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“…The configuration of the stereogenic carbon atoms of СH(OH)P fragments in the racemic 11-13 and meso 8-10 forms of the calixarene-bis-α-hydroxymethylphosphonates were determined from signal patterns of aromatic protons in para-unsubstituted benzene rings (see 36 for a comparison). In the racemic form 11 possessing C 2 symmetry axis the protons appear as three doublets of doublets.…”

Section: Scheme 2 Synthesis Of Dipropoxycalixarene-bis-α-hydroxymethmentioning

confidence: 99%

Calix[4]arene-α-hydroxyphosphonic acids. Synthesis, stereochemistry, and inhibition of glutathione S-transferase

Cherenok¹,

Yushchenko²,

Tanchuk³

et al. 2012

Arkivoc

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A series of dipropoxy-, tripropoxy-and tetrapropoxycalix[4]arenes bearing one or two fragments of α-hydroxymethylphosphonic acid at the upper rim of the macrocycle was prepared by the reaction of the corresponding mono-and di-formylcalixarenes with sodium salts of dialkyl phosphites or with trialkyl (tristrimethylsilyl)phosphites followed by dealkylation (desilylation) of the ester derivatives. The conformations of the macrocyclic skeleton and the stereoisomeric forms of the compounds obtained were investigated by 1 H NMR. The resulting α-hydroxymethylphosphonic acids were found to be able to inhibit the activity of glutathione Stransferase in vitro.

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Calix[4]arenes with perfluorinated alcoholic functions at the upper rim: a new class of neutral anion receptors

Cited by 33 publications

References 19 publications

Biomimetic macrocyclic receptors for carboxylate anion recognition based on C -linked peptidocalix[4]arenes

Biomimetic macrocyclic receptors for carboxylate anion recognition based on C -linked peptidocalix[4]arenes

Calix[4]arene Anion Receptors Bearing 2,2,2-trifluoroethanol Groups at TheUpperRim

Calix[4]arene-α-hydroxyphosphonic acids. Synthesis, stereochemistry, and inhibition of glutathione S-transferase

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