Chiral piperazine-2,5-dione derivatives as effective alpha-glucosidase inhibitors. Part 4.

The potential to inhibit alpha- and beta-glucosidases of a series of chiral piperazine-2,5-dione derivatives was investigated. Three of the seven compounds tested, viz., 1, 5b, and 5c, showed to be non competitive inhibitors of alpha-glucosidase, whereas they exhibited very low inhibitory activity towards beta-glucosidase.

Computational DFT investigation of vicinal amide group anchimeric assistance in ether cleavage.

Density functional theory (DFT) computations in solvent have been used to investigate the mechanism of anchimeric assistance (by a vicinal amide group) in the acid-induced ether cleavage. The calculations were carried out at the B3LYP/6-31G* level of theory via full geometry optimizations within the IEF-PCM continuum solvent model. Two different mechanisms have been investigated here that were previously hypothesized for the rate-determining step of this process: the first (mechanism A1) involves a protonated amide and an ethereal oxygen as the nucleophile, while the second (mechanism A2) involves protonation of the ethereal oxygen followed by a nucleophilic attack of the amide.

Kinetics and Mechanism of Aminolysis of Phenyl Acetates in Aqueous Solutions of Poly(ethylenimine).

Second-order rate constants (k(n)) for the aminolysis of some phenyl acetates with poly(ethylenimine) (PEI) were obtained in a pH range 4.36-11.20 at 25 degrees C in 1 M KCl.