Water-Soluble Calixarene as the First Man-Made Catalyst for Regioselective Cleavage of Ribonucleoside 2′,3′-Cyclic Phosphate

The P–O(2′) bond of cytidine 2′,3′-cyclic phosphate, an intermediate in RNA hydrolysis, is regioselectively cleaved at pH 2 by use of water-soluble calix[4]arene-5,11,17,23-tetrasulfonate. This is the first totally man-made mimic for the regioselective catalysis of ribonuclease.