反应详情

(This compound was prepared in close analogy to the method of Perez et al., Spanish patent appl. ES 493-459.) 2-Methyl-2H-pyrazole-3,4-dicarboxylic acid diethyl ester (2.06 g, 9.1 mmol) was suspended in a NaOH solution (0.5M in water, 20 ml, 10 mmol) and heated to reflux (30 min). If the conversion was incomplete after this time, as indicated by HPLC control, small amounts of NaOH were added in 30 min intervals. The reaction mixture was cooled, and HCl was added, and stirred for an additional 30 min (r.t.). The precipitate was filtered, washed (water, small amount) and dried under vacuum. The title compound was obtained as a white solid (1.27 g, 70%), and was used in the next step without further purification. MS (m/e)=198 [M+H+].

1. custom(This compound was prepared in close analogy to the method of Perez et al., Spanish patent appl
2. temperatureheated
3. temperatureto reflux (30 min)
4. additionwere added in 30 min intervals
5. temperatureThe reaction mixture was cooled
6. filtrationThe precipitate was filtered
7. washwashed (water, small amount)
8. customdried under vacuum