MEK inhibitors: the chemistry and biological activity of U0126, its analogs, and cyclization products.

In search of antiinflammatory drugs with a new mechanism of action, U0126 was found to functionally antagonize AP-1 transcriptional activity via noncompetitive inhibition of the dual specificity kinase MEK with an IC50 of 0.07 microM for MEK 1 and 0.06 microM for MEK 2. U0126 can undergo isomerization and cyclization reactions to form a variety of products, both chemically and in vivo, all of which exhibit less affinity for MEK and lower inhibition of AP-1 activity than parent, U0126.

Pyrazoles, 1,2,4-triazoles, and tetrazoles as surrogates for cis-amide bonds in boronate ester thrombin inhibitors.

Substituted pyrazoles, 1,2,4-triazoles, and tetrazoles are good surrogates for cis-amide bonds in a series of boronate ester thrombin inhibitors.

Discovery of an orally active series of isoxazoline glycoprotein IIb/IIIa antagonists.

Using isoxazoline XR299 (1a) as a starting point for the design of highly potent, long-duration GPIIb/IIIa antagonists, the effect of placing lipophilic substituents at positions alpha and beta to the carboxylate moiety was evaluated. Of the compounds studied, it was found that the n-butyl carbamate 24u exhibited superior potency and duration of ex vivo antiplatelet effects in dogs. Replacement of the benzamidin-4-yl moiety with alternative basic groups, elimination of the isoxazoline stereocenter, and reversal of the orientation of the isoxazoline ring resulted in lowered potency and/or duration of action.

Design, synthesis, and structure--activity relationship studies for a new imidazole series of J774 macrophage specific acyl-CoA:cholesterol acyltransferase (ACAT) inhibitors.

Acyl-CoA:cholesterol acyltransferase (ACAT) is the primary enzyme involved in intracellular cholesterol esterification. Arterial wall infiltration by macrophages and subsequent uncontrolled esterification of cholesterol leading to foam cell formation is believed to be an important process which leads to the development of fatty streaks. Inhibitors of the ACAT enzyme may retard this atherogenic process. We have recently discovered a series of imidazoles which are potent in vitro ACAT inhibitors in the J774 macrophage cell culture assay. This paper will describe the design, synthesis, and structure--activity relationship for this very potent series of compounds.

Acyl CoA:cholesterol acyltransferase (ACAT) inhibitors: synthesis and structure-activity relationship studies of a new series of trisubstituted imidazoles.

A series of 4,5-diaryl-2-(substituted thio)-1H-imidazoles has been synthesized and demonstrated to be potent inhibitors of acyl-CoA:cholesterol acyltransferase (ACAT). The design, synthesis, and structure-activity relationships for this series are reported herein. One of the compounds from this series, N'-(2,4-difluorophenyl)-N-[5-[(4,5-diaryl-1H-imidazol-2- yl)thio]pentyl]-N-heptylurea (DuP 128), was selected for development as an intestinally active ACAT inhibitor. DuP 128 is a potent ACAT inhibitor in vitro and in vivo, inhibiting ACAT in rat hepatic microsomes with an IC50 = 10 nM and possessing potent antihypercholesterolemic activity in vivo.