Nitric Acid → 5-Methyl-4-[2-(7-nitro-benzothiophene-4-yloxy)-ethyl]-2-phenyl-oxazole

Participants

Reaction Conditions

Reaction Steps

286 g (0.853 mol) of 4-[2-(benzothiophene-4-yloxy)-ethyl]-5-methyl-2-phenyl-oxazole were suspended in 6.3 l of glacial acetic acid. Temperature was raised to 60 ° C. The resulting clear solution was cooled to 25° C. 132 ml (3.18 mol) of 100% nitric acid were added within 3 minutes. The reaction mixture was cooled below 30° C. After crystallization the suspension was stirred at 18 to 20° C. for 1 hour. The precipitate was filtered with suction and washed with 2×600 ml of tert-butyl methyl ether. The residue was suspended in 4 l of acetic ester for 15 minutes. 200 g (1.9 mol) of sodium carbonate in 3 l water were added. The resulting suspension was stirred for 1 hour. Acetic ester was distilled off followed by addition of 2 l of water. The suspension was stirred for 30 minutes. The precipitate was filtered with suction, washed with water and dried (50° C., 24 hours).

Provenance & Evidence