Design, Synthesis, and Biological Evaluation of 5-Formyl-pyrrolo[3,2-b]pyridine-3-carboxamides as New Selective, Potent, and Reversible-Covalent FGFR4 Inhibitors

Abstract

The FGF19-FGFR4 signaling pathway has been extensively studied as a promising target for the treatment of hepatocellular carcinoma (HCC). Several FGFR4-selective inhibitors have been developed, but none of them receives approval. Additionally, acquired resistance caused by FGFR4 gatekeeper mutations is emerging as a serious limitation for these targeted therapies. Herein, we report a novel series of 5-formyl-pyrrolo[3,2-b]pyridine derivatives as new reversible-covalent inhibitors targeting wild-type and gatekeeper mutant variants of FGFR4 kinase. The representative compound 10z exhibited single-digit nanomolar activity against wild-type FGFR4 and the FGFR4V550L/M mutant variants in biochemical and Ba/F3 cellular assays, while sparing FGFR1/2/3. Furthermore, 10z showed significant antiproliferative activity against Hep3B, JHH-7, and HuH-7 HCC cells with IC50 values of 37, 32, and 94 nM, respectively. MALDI-TOF-MS and X-ray protein crystallography studies were consistent with 10z acting as a reversible-covalent inhibitor of FGFR4, serving as a promising lead compound for further anticancer drug development.

Discovery of 6-Formylpyridyl Urea Derivatives as Potent Reversible-Covalent Fibroblast Growth Factor Receptor 4 Inhibitors with Improved Anti-Hepatocellular Carcinoma Activity

“…Additionally, our previous studies had demonstrated that an (R)-3,5-dichloropyridine-4-yl ethoxy group favorably increased cellular activity by introducing additional interactions with FGFR4 based on a pan-FGFR inhibitor, LY2874455. 27 Thus, replacement of the methoxyethylamino group of 8l with an (R)-3,5-dichloropyridine-4-yl ethoxy group led to compound 8m. While compound 8m showed a 2-fold decrease in FGFR4 biochemical inhibitory 2).…”

“…In our effort to discover novel reversible-covalent FGFR4 inhibitors, we identified the 5-formyl-pyrrolo [3,2-b]pyridine-3carboxamide (5-PPC, 8a) as a selective FGFR4 inhibitor starting point for a scaffold-hopping strategy. 27 Compound 8a possesses a pyrrolo [3,2-b]pyridine core instead of the original tetrahydronaphthyridine core. We found that compound 8a displayed nanomolar activity against FGFR4 in a biochemical assay (IC 50 = 10.0 nM) and suppressed the growth of engineered Ba/F3 cells harboring FGFR4 (Ba/F3-FGFR4) with an IC 50 value of 11.8 nM, while sparing FGFR1/2/3 (IC 50 > 10 μM).…”

“…The designed molecules were prepared starting from ethyl 6bromo-5-(1,3-dioxolan-2-yl)-1H-pyrrolo [3,2-b]pyridine-3-carboxylate (9) that we have previously reported. 27 As showed in Scheme 1, alkylation of 9 with iodomethane or 2-bromopropane Otherwise, coupling 12b with potassium vinyltrifluoroborate ethylene borate obtained 13h; then oxidation with sodium periodate gave the aldehyde 14. Further condensation of 14 with propyl N-(2-aminoethyl)-N-methylglycinate (15) yielded intermediates 16a−16c, which were deprotected with 2.0 M HCl to obtain the designed compounds 8j−8l.…”

“…The synthesis and structural characterization of compound 8a has been previously reported. 27 The synthesis of 8m−8ze is described in Scheme 2. Nucleophilic substitution reaction with 6-bromo-2-nitro-pyridin-3-ol (17) and various halides produced 18a−18e.…”

“…In this article, we describe the design, synthesis, and biological evaluation of the representative (R)-1-(5-cyano-4-(1-(3,5-dichloropyridin-4yl)ethoxy)pyridin-2-yl)-3-(6-formyl-5-((4-methyl-2-oxopiperazin-1-yl)methyl)-3-(2-morpholinoethoxy)pyridin-2-yl)urea (8z) as a selective reversible-covalent FGFR4 inhibitor with improved metabolic stability and potent anti-HCC activity in vitro and in vivo based on 5-formyl-pyrrolo [3,2-b]pyridine-3carboxamide (8a) reported by our group (Figure 2). 27 ■ CHEMISTRY…”