反应详情

A solution of 1-(3-methoxyphenyl)-3,5-dimethyl-1H-pyrazole 1 (7.10 g, 35.11 mmol) in hydrogen bromide acid (45 mL, 48%) refluxed (110-120° C.) for 19 hours under a nitrogen atmosphere. Then the mixture was cooled to ambient temperature and neutralized with a solution of K2CO3 in water until there was no gas to generate. Then the precipitate was filtered off and washed with water several times. The collected solid was dried in air under reduced pressure to afford the product as a brown solid (6.33 g in 96% yield). 1H NMR (DMSO-d6, 400 MHz): δ 2.16 (s, 3H), 2.28 (s, 3H), 6.04 (s, 1H), 6.75-6.77 (m, 1H), 6.86-6.89 (m, 2H), 7.26 (t, J=8.0 Hz, 1H), 9.73 (s, 1H). 13C NMR (DMSO-d6, 100 MHz): δ 12.29, 13.30, 107.07, 111.10, 113.94, 114.43, 129.71, 138.95, 140.70, 147.57, 157.84.

1. filtrationThen the precipitate was filtered off
2. washwashed with water several times
3. customThe collected solid was dried in air under reduced pressure