Artificial esterases

An octa(dimethylaminopropyl)calixresorcin[4]arene [243 R = CH2CONH(CH2)3 NMc 2] is a primitive artificial esterase for 4-nitrophenyl esters of various carboxylic acids. The overall mechanism is thought to involve complexation of substrate with the arene in its neutral form followed by infracomplex reaction of a dimetiiylamino function... 

Currently there is considerable interest in developing artificial esterases and peptidases that hydrolyse esters and amides. The first nonenzymatic, catalytic hydrolysis of methyl acetate and acetylcholine in neutral water at 25 has now been described. The complex [Co(trpn)(OH)(OH2)] (10) catalyzes the hydrolysis of methyl acetate at pH 7.6. The reaction is believed to involve the steps shown... 

Pirrincioglu N, Zaman F, Williams A. A calixresorcinarene provides the framework for an artificial esterase. J Chem Soc Perkin Trans 1996 2(12) 2561-2. 

Metal Complexes of Calixarenes as Artificial Esterases or Phosphodiesterases... 

Receptor 44 is an artificial esterase featuring a zinc(II)-salophen unit appended to a resorcinarene scaffold [39]. The basic hydrolysis of PNPCC in buffered CH2CI2 containing 0.01 % water (Eq. 26.8) is more than 50 times faster in the presence of the catalyst. The substrate shows a very high affinity for 44. The trimethy-lammonium head is hosted deep in the receptor cavity and the ester function is properly oriented towards the metal electrophile of the catalytic site. 

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