2,6-Difluoro-3-(propylsulfonaMido)benzoic acid

Uses

2,6-Difluoro-3-(propylsulfonaMido)benzoic acid is a BRAF inhibitor approved by the US FDA in 2011, primarily used to treat advanced melanoma. Clinical studies have shown that vemurafenib exhibits significant resistance, but patients show disease remission within the first few months of its application.

Synthesis

Example C: Synthesis of 2,6-difluoro-3-(propylsulfonamido)benzoic acid An aqueous 1N NaOH solution (150 mL, 150 mmol) was added to a 4:1 THF/MeOH (250 mL, 0.2 M) solution of methyl 2,6-difluoro-3-(N-propylsulfonyl)benzoate (20.0 g, 50.1 mmol). The reaction mixture was stirred at room temperature overnight. Most of the organic solvent was removed under vacuum (water bath temperature 35 °C). To the residue, 1N HCl (150 mL) was slowly added, and the resulting solid was filtered and washed with water (4 x 50 mL). Subsequently, the solid was washed with ether (4 x 15 mL) to afford 2,6-difluoro-3-(propylsulfonamido)benzoic acid as a white solid (10.7 g, 77% yield). 1H NMR (400 MHz, d6-DMSO) δ 9.74 (s, 1H), 7.57-7.50 (m, 1H), 7.23-7.17 (m, 1H), 3.11-3.06 (m, 2H), 1.79-1.69 (m, 2H), 0.98 (t, J = 7.4 Hz, 3H). m/z (APCI-neg) M-1 = 278.0.

References

[1] Patent: WO2011/25938, 2011, A2. Location in patent: Page/Page column 52
[2] Patent: WO2011/25940, 2011, A1. Location in patent: Page/Page column 57-58
[3] Patent: WO2011/25947, 2011, A1. Location in patent: Page/Page column 40
[4] Patent: WO2011/25965, 2011, A1. Location in patent: Page/Page column 38
[5] Patent: WO2011/25951, 2011, A1. Location in patent: Page/Page column 31-32