Potent and selective mitogen-activated protein kinase kinase (MEK) 1,2 inhibitors. 1. 4-(4-bromo-2-fluorophenylamino)-1- methylpyridin-2(1H)-ones.

The role of MEK 1,2 in cancer tumorgenesis has been clearly demonstrated preclinically, and two selective inhibitors are currently undergoing clinical evaluation to determine their role in the human disease. We have discovered 4-(4-bromo-2-fluorophenylamino)-1-methylpyridin-2(1H)-ones as a new class of ATP noncompetitive MEK inhibitors. These inhibitors exhibit excellent cellular potency and good pharmacokinetic properties and have demonstrated the ability to inhibit ERK phosphorylation in HT-29 tumors from mouse xenograft studies.

Potent, low-calcemic, selective inhibitors of CYP24 hydroxylase: 24-sulfone analogs of the hormone 1alpha,25-dihydroxyvitamin D3.

The new 24-phenylsulfone 4a, a low-calcemic analog of the natural hormone 1alpha,25-dihydroxyvitamin D(3), is a potent (IC(50) = 28nM) and highly selective inhibitor of the human 24-hydroxylase enzyme CYP24.