Synthesis and Evaluation of 1,3-Disubstituted Imidazolidine-2,4,5-triones as Inhibitors of Pyruvate Carboxylase.

Substituted imidazolidinetriones (IZTs) have been identified as potent inhibitors of pyruvate carboxylase (PC) through an in silico screening approach. Alkyl 2-(2,4,5-trioxo-3-substituted imidazolidin-1-yl)acetates (6i-6r) are the most potent of the series, with IC50 values between 3 and 12 µM, and several IZTs demonstrate high passive permeability across an artificial membrane. IZTs are mixed-type inhibitors with respect to pyruvate and noncompetitive with respect to ATP. This class of inhibitors appears to be selective for PC. Inhibitors in the IZT series do not inhibit the metalloenzymes human carbonic anhydrase II and matrix metalloprotease-12, and they do not inhibit the related biotin-dependent enzyme, guanidine carboxylase. Altogether, IZTs offer promise as PC inhibitors with potential downstream applications in cellular and in vivo systems.

Synthesis and Evaluation of 5-(Heteroarylmethylene)hydantoins as Glycogen Synthase Kinase-3ß Inhibitors.

Glycogen synthase kinase-3 (GSK-3) is a serine/threonine kinase which plays a center role in the phosphorylation of a wide variety of proteins, generally leading to their inactivation. As such, GSK-3 is viewed as a therapeutic target. An ever-increasing number of small organic molecule inhibitors of GSK-3 have been reported. Phenylmethylene hydantoins are known to exhibit a wide range of inhibitory activities including for GSK-3ß. A family of fourteen 2-heterocycle substituted methylene hydantoins (14, 17-29) were prepared and evaluated for the inhibition of GSK-3ß at 25 µM. The IC50 values of five of these compounds was determined; the two best inhibitors are 5-[(4'-chloro-2-pyridinyl)methylene]hydantoin (IC50 = 2.14 ± 0.18 µM) and 5-[(6'-bromo-2-pyridinyl)methylene]hydantoin (IC50 = 3.39 ± 0.16 µM). The computational docking of the compounds with GSK-3ß (pdb 1q41) revealed poses with hydrogen bonding to the backbone at Val135. The 5-[(heteroaryl)methylene]hydantoins did not strongly inhibit other metalloenzymes, demonstrating poor inhibitory activity against matrix metalloproteinase-12 at 25 µM and against human carbonic anhydrase at 200 µM, and were not inhibitors for Staphylococcus aureus pyruvate carboxylase at concentrations >1000 µM.