Sulfuric Acid → 2-(3-Difluoromethyl-5-phenyl-pyrazol-1-yl)-5-methanesulfonyl-pyridine

Participants

Reaction Steps

To 120 g of 5-(methylsulfonyl)-2-hydrazinyl-pyridine [CP-675,775] (0.641 moles) was charged isopropanol (900 mL) followed by 4,4-difluoro-1-phenyl-1,3-butanedione (122 g, 0.615 moles, 0.96 eq.) as a melt, followed by 900 mL of isopropanol. The slurry was stirred for 15 minutes, then 36 mL of concentrated sulfuric acid was added (slight exotherm) (15 volumes of isopropanol total). The reaction was stirred for 6 hours at 20-30° C., 2.4 L (20 volumes) of water was added (slight exotherm, reaction temperature kept below 45° C.) and the reaction was granulated for 2 days. The product was filtered and was rinsed with water. The product contained less than 0.5% of compound 6 (retention time 5.1 minutes). Analytical data: HPLC retention time (title compound) 8.4 minutes; MS: 349.36 (calc), M+1=350.1; 1H NMR in CDCl3: 8.75 doublet, (1H), 8.26 Quartet (1H), 7.38 multiplet (3H), 7.36 doublet (2H), 6.70 multiplet (2H), 3.08, Singlet, (3H); 13C NMR in CDCl3: 15.3, 149.3, 147.9, 146.6, 138.1, 130.27, 133.5, 130.0, 129.1, 128.7, 117.9, 113.4, 111.1, 108.1, 107.7, 45.

Provenance & Evidence