Kinetic analysis of ester aminolysis catalyzed by nucleosides in a nonpolar medium. Evidence of bifunctional catalysis

Kinetic analysis of ester aminolysis in benzene catalyzed by 2',3',5'-O-tris(tert-butyldimethylsilyl) protected nucleosides and 2-pyridone is reported. The catalytic rate constant k(3), was determined for protected nucleosides A, C, G, U, and pseudouridine (Psi). The relatively high value associated with C and 2-pyridone is indicative of bifunctional catalysis occurring through stabilization of the aminolysis transition state. The implications of this finding on the possible role C plays in biological catalysis during protein synthesis is hypothesized.