Synthesis of 3-[(N-carboalkoxy)ethylamino]-indazole-dione derivatives and their biological activities on human liver carbonyl reductase.

A series of indazole-dione derivatives were synthesized by the 1,3-dipolar cycloaddition reaction of appropriate substituted benzoquinones or naphthoquinones and N-carboalkoxyamino diazopropane derivatives. These compounds were evaluated for their effects on human carbonyl reductase. Several of the analogs were found to serve as substrates for carbonyl reductase with a wide range of catalytic efficiencies, while four analogs display inhibitory activities with IC(50) values ranging from 3-5 microM. Two of the inhibitors were studied in greater detail and were found to be noncompetitive inhibitors against both NADPH and menadione with K(I) values ranging between 2 and 11 microM. Computational studies suggest that conformation of the compounds may determine whether the indazole-diones bind productively to yield product or nonproductively to inhibit the enzyme.

Synthesis and MEK1 inhibitory activities of imido-substituted 2-chloro-1,4-naphthoquinones.

Mitogen activated protein kinases are of interest as research tools and as therapeutic target for certain physiological disorders. In this study, we found 2-chloro-3-(N-succinimidyl)-1,4-naphthoquinone 6 to be a selective inhibitor of MEK1 with an IC(50) of 0.38 microM. An open-chain homologue, 10, showed selective cytotoxicity against renal cancer in the NCI in vitro tumor screening. Structure-activity relationship study of eight compounds showed the cyclic imido-substituted chloro-1,4-naphthoquinone as more potent and selective MEK1 inhibitors than the open chain homologues. The imido-substituted chloro-1,4-naphthoquinones were synthesized in a straightforward fashion by refluxing 2-amino-3-chloro-1,4-naphthoquinone with the appropriate acid chloride or diacyl dichloride.