Benzoxazole, 5-fluoro-2-methyl-6-nitro- synthesis

Yield:40703-40-0 1.85 g

Reaction Conditions:

with sulfuric acid;nitric acid at 0 - 20; for 1 h;

Steps:

92.b (b) 5-Fluoro-2-methyl-6-nitrobenzo[d]oxazole

(b) 5-Fluoro-2-methyl-6-nitrobenzo[d]oxazole (2667) To a solution of 5-fluoro-2-methylbenzo[d]oxazole (1 .65 g) in sulfuric acid (10 ml) was added a mixture of nitric acid (2.5 m) and sulfuric acid (2.5 ml) at 0 °C. The reaction was allowed to stir at room temperature for 30 minutes whereupon LCMS indicated complete conversion. After 1 hour, the reaction was slowly poured onto crushed ice then diluted with water. After stirring 20 minutes, the solids were collected, rinsed well with water, and suction dried to afford the titled compound (1 .85 g) as a pink solid. LCMS m/z = 196.9 [M+H]. NMR (400 MHz, DMSO-d₆) δ ppm 2.71 (s, 3H), 7.97 (d, J=1 1 .12 Hz, 1 H), 8.64 (d, J=6.32 Hz, 1 H).

References:

WO2017/98421,2017,A1 Location in patent:Page/Page column 223