Phosphorus oxychloride → HCID 58431286, compound

Participants

Reaction Steps

A solution of 3-fluoro-2-(trifluoromethyl)isonicotinic acid 1-oxide (1.0 g, 4.4 mmol from Step A) in phosphoryl chloride (4 mL, 40 mmol) was heated to 110° C. for 2 hours, then was left to stir at ambient temperature overnight. The POCl3 was evaporated, the residue was treated with sodium bicarbonate solution, which was stirred for 1 hour. To this mixture was added tetrahydrofuran (20 mL) and lithium hydroxide monohydrate (0.24 g, 5.7 mmol). This was stirred for 3 hours. The pH of the mixture was then adjusted to the range of pH 4-5 by the addition of c.HCl. The product was extracted with three portions of ethyl acetate. The combined extracts were dried over sodium sulfate, filtered and concentrated. Yield: 0.54 g (50%); LC-MS: 244.1/245.9 (M+H)+. 1H NMR (300 MHz, CDCl3): δ 8.07 (d, 1H).

Provenance & Evidence