835621-07-3

BAY 73-4506 (Regorafenib) is a multikinase inhibitor with IC50 of 17, 40 and 69 nM c-KIT, VEGFR2, B-Raf.

GENERAL STEPS: 4-(4-(3-(4-chloro-3-(trifluoromethyl)phenyl)ureido)-3-fluorophenoxy)-N-methylpyridine amide (free base, 2.0 g) was dissolved in anhydrous tetrahydrofuran (15 mL) and 4M HCl/dioxane solution was slowly added (to excess). Upon completion of the reaction, the mixed solution was concentrated under reduced pressure to give 2.32 g of off-white solid. The resulting crude product was dissolved in preheated ethanol (125 mL), appropriate amount of activated carbon was added and heated to reflux for 15 minutes. Subsequently, the hot suspension was filtered through a diatomaceous earth pad (model 521) and cooled to room temperature. The filtrate was placed in a refrigerator overnight to promote crystallization. On the following day, the crystallized product was collected by diafiltration, washed sequentially with cold ethanol and hexane, and air-dried. The mother liquor was further concentrated and the above crystallization process was repeated (overnight in a refrigerator) to collect the second batch of crystalline product and combined with the first batch. Finally, the resulting colorless hydrochloride product was dried in a vacuum oven at 60°C for two days to give a final product of 1.72 g (79% yield). Melting point: 215°C. Elemental analysis (calculated/measured): C 48.57/48.68, H 3.11/2.76, N 10.79/10.60, Cl 13.65/13.63, F 14.63/14.88.

Regorafenib potently inhibits VEGFR2 autophosphorylation in NIH-3T3/VEGFR2 cells with an IC50 of 3 nM. In HAoSMCs, regorafenib inhibits PDGFR-β autophosphorylation after stimulation with PDGF-BB, with an IC50 of 90 nM. Regorafenib inhibits the proliferation of VEGF165-stimulated HUVECs, with an IC50 of 3 nMf. Regorafenib causes a concentration-dependent decrease in Hep3B cell growth, having an IC50 of 5 μM. Regorafenib subsequently increases the levels of phospho-c-Jun, a JNK target, but not total c-Jun in Hep3B cells.

Regorafenib effectively inhibits growth of the Colo-205 xenografts in the dose range of 10-100 mg/kg reaching a TGI of 75% at day 14 at the 10 mg/kg dose. In the MDA-MB-231 model, regorafenib is highly efficacious at a dose as low as 3 mg/kg, resulting in a significant TGI of 81%, which increases to 93% at doses of 10 and 30 mg/kg, where tumor stasis is reached.

VEGFR1: 13 nM (IC₅₀); VEGFR2: 4.2 nM (IC₅₀); VEGFR3: 46 nM (IC₅₀); PDGFRβ: 22 nM (IC₅₀); Braf: 28 nM (IC₅₀); BRaf^V600E: 19 nM (IC₅₀); Raf-1: 2.5 nM (IC₅₀)

[1] Phan, Chiuyen et al. “Isomorphous Crystals Formed by the Similar Supramolecular Motifs in Sorafenib Hydrochloride and Regorafenib Hydrochloride Salts.” 2019. 0.