反应详情

To an ice-cooled and stirred solution of 2.9 g (18.8 mmol) 5-isopropylpyrazol-3-carboxylic acid II (lit.: Baraldi P. G. et al: Farmaco, 46, 1337 (1991); mp=136-140° C.) in fuming sulphuric acid (65%) the nitric acid (65%) was added portion wise. The stirring was continued for 1 h at room temperature and then another 3 h at 104° C. temperature and then poured into ice-water. The white precipitate of product was filtered and crystallized from water; (yield 76%); mp=139-142° C.; 1H NMR (300 MHz, DMSO): 1.22 d (6H, 7.1 Hz), 2.94 sept (1H, 7.1 Hz), 3.33 s (1H), 6.45 bs (1H); CHN required: C=42.02%; H=4.56%; N=21.09; found: C=42.41%; H=4.49%; N=21.01%.

1. additionwas added portion wise
2. filtrationThe white precipitate of product was filtered
3. customcrystallized from water