The cone-calix[4]arene derivative (1H3 )^2+ decorated at the upper rim with two guanidinium units and a phenolic hydroxyl in an ABAH functionalization pattern, effectively promotes the cleavage of the DNA model compound bis(p-nitrophenyl) phosphate (BNPP) in 80% DMSO solution at pH values in the range 8.5 − 12.0. The pH dependence of the kinetics was found to be fully consistent with the results of the potentiometric titration of the triprotic acid (1H 3)^2+. At pH 9.5, the rate enhancement of p-nitrophenol liberation from BNPP relative to background hydrolysis is 6.5 × 10^4-fold at 1 mM concentration of the calix[4]arene derivative. Experimental data clearly point to the e ff ective cooperation of the three active units and to the involvement of the phenolate moiety as a nucleophile in the phosphoryl transfer step. Subsequent liberation of a second equivalent of p-nitrophenol from the phosphorylated calixarene intermediate is conceivably promoted by the “ built-in ”guanidine/guanidinium catalytic dyad.
Phosphoryl transfer processes promoted by a trifunctional Calix[4]arene inspired by DNA topoisomerase I / Salvio, Riccardo; Volpi, Stefano; Cacciapaglia, Roberta; Sansone, Francesco; Mandolini, Luigi; Casnati, Alessandro. - In: JOURNAL OF ORGANIC CHEMISTRY. - ISSN 1520-6904. - STAMPA. - 81:(2016), pp. 9012-9019. [10.1021/acs.joc.6b01643]
Phosphoryl transfer processes promoted by a trifunctional Calix[4]arene inspired by DNA topoisomerase I
SALVIO, RICCARDO;MANDOLINI, Luigi;
2016
Abstract
The cone-calix[4]arene derivative (1H3 )^2+ decorated at the upper rim with two guanidinium units and a phenolic hydroxyl in an ABAH functionalization pattern, effectively promotes the cleavage of the DNA model compound bis(p-nitrophenyl) phosphate (BNPP) in 80% DMSO solution at pH values in the range 8.5 − 12.0. The pH dependence of the kinetics was found to be fully consistent with the results of the potentiometric titration of the triprotic acid (1H 3)^2+. At pH 9.5, the rate enhancement of p-nitrophenol liberation from BNPP relative to background hydrolysis is 6.5 × 10^4-fold at 1 mM concentration of the calix[4]arene derivative. Experimental data clearly point to the e ff ective cooperation of the three active units and to the involvement of the phenolate moiety as a nucleophile in the phosphoryl transfer step. Subsequent liberation of a second equivalent of p-nitrophenol from the phosphorylated calixarene intermediate is conceivably promoted by the “ built-in ”guanidine/guanidinium catalytic dyad.File | Dimensione | Formato | |
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