Development of Novel, Highly Potent Inhibitors of V-RAF Murine Sarcoma Viral Oncogene Homologue B1 (BRAF): Increasing Cellular Potency through Optimization of a Distal Heteroaromatic Group

Abstract

We describe the design, synthesis, and optimization of a series of new inhibitors of V-RAF murine sarcoma viral oncogene homologue B1 (BRAF), a kinase whose mutant form (V600E) is implicated in several types of cancer, with a particularly high frequency in melanoma. Our previously described inhibitors with a tripartite A-B-C system (where A is a hinge binding pyrido[4,5-b]imidazolone system, B is an aryl spacer group, and C is a heteroaromatic group) were potent against purified (V600E)BRAF in vitro but were less potent in accompanying cellular assays. Substitution of different aromatic heterocycles for the phenyl based C-ring is evaluated herein as a potential means of improving the cellular potencies of these inhibitors. Substituted pyrazoles, particularly 3-tert-butyl-1-aryl-1H-pyrazoles, increase the cellular potencies without detrimental effects on the potency on isolated (V600E)BRAF. Thus, compounds have been synthesized that inhibit, with low nanomolar concentrations, (V600E)BRAF, its downstream signaling in cells [as measured by the reduction of the phosphorylation of extracellular regulated kinase (ERK)], and the proliferation of mutant BRAF-dependent cells. Concomitant benefits are good oral bioavailability and high plasma concentrations in vivo.

Paradox-Breaking RAF Inhibitors that Also Target SRC Are Effective in Drug-Resistant BRAF Mutant Melanoma

“…As previously described, we have pursued a drug discovery program in which we designed, synthesized, and characterized inhibitors of the inactive conformation of BRAF V600E ( Ménard et al., 2009; Niculescu-Duvaz et al., 2009; Suijkerbuijk et al., 2010; Whittaker et al., 2010b; Zambon et al., 2010 ). Here, we describe two further inhibitors, CCT196969 and CCT241161 ( Figure 1 A; synthesis and characterization are described in the Supplemental Experimental Procedures available online).…”

Facile Synthesis, Structural Activity Relationship, Molecular Modeling and In Vitro Biological Evaluation of New Urea Derivatives with Incorporated Isoxazole and Thiazole Moieties as Anticancer Agents

“…It is worth to mention that, Mishra et al prepared the urea derivative 17 by the reaction of the p ‐tolylisocyanate and 4‐amino‐ N ‐(5‐methylisoxazol‐3‐yl)benzenesulfonamide in DMF at reflux for 5–6 hours. Also, the compound 18 has been prepared in different methods as described in the literatures . In the same manner, the reaction of benzoyl isocyanate 10 , with the amines 2 , 3 and 6 in acetonitrile gave the urea derivatives 19 , 20 and 21 in moderate to good yields (56 – 65%).…”

A simple synthesis of 4-aroyl-5-methyl-1H-imidazol-2(3H)-one derivatives (Enoxymone analogues) from aryl methyl ketones via enaminones

“…(Z)-1-(4-bromophenyl)-3-(dimethylamino)but-2-en-1-one (2e) (2.81 g, 10.5 mmol) was dissolved in MeOH (50 mL) NH 4 OAc was added (7.7 g, 100 mmol) and the reaction mixture was stirred for 2 h at room temperature. Volatile components were evaporated and the product was isolated by column chromatography (EtOAc/petroleum ether = 1:1 -1-(4-(methylsulfonylphenyl)-1-oxobut-2-en-2-yl)hydrazine-1,2-dicarboxylate (4d) (Z)-3-amino-1-(4-(methylsulfonylphenyl)but-2-en-1-one (3d) (570 mg, 2.38 mmol) was dissolved in MeCN (10 mL) DEAD was added (408 µL, 2.6 mmol) and reaction mixture stirred for 12 h at room temperature Volatile components were evaporated and the product was isolated by column chromatography (EtOAc/petroleum ether = 1:1).…”

“…(E)-3-(dimethylamino)-1-phenylbut-2-en-1-one 29 (2b) (3.78 g, 20 mmol) was disolved in MeOH (50 mL) NH 4 OAc was added (15.4 g, 200 mmol) and the reaction mixture was stirred for 3 h at room temperature. Volatile components were evaporated and the product, (Z)-3-amino-1-phenylbut-2-en-1-one, 30 was isolated by column chromatography (EtOAc/petroleum ether = 1:1) and used directly in the next step.…”