Electric Literature of 37622-90-5, A common heterocyclic compound, 37622-90-5, name is Ethyl 4-pyrazolecarboxylate, molecular formula is C6H8N2O2, its traditional synthetic route has been very mature, but the traditional synthetic route has various shortcomings, such as complicated route, low yield, poor purity, etc, below Introduce a new synthetic route.
To a solution of ethyl 1H-pyrazole-4-carboxylate (5.4 g, 38.5 mmol) in t-butanol (20 mL) was added conc. H2SO4 (4 mL, 73.5 mmol) at 15 oC. The mixture was stirred at 100 oC for 14 hours. The reaction was quenched with water (30 mL) and extracted with ethyl acetate (40 mL x3). The organic phase was washed with 2M NaOH (20 mL x2) and the aqueous was acidified with conc. HCl to pH~2 and extracted with ethyl acetate (30 mL x5). The combined organic phases were dried over anhydrous Na2SO4, filtered and concentrated to afford 1-(tert-butyl)-1H- pyrazole-4-carboxylic acid as a white solid.1H NMR (400 MHz, DMSO-d6) delta 12.17 (br, 1 H); 8.24 (s, 1 H); 7.81 (s, 1 H); 1.52 (s, 9 H).
The basis of chemical reaction formula synthesis, the synthesis route is composed of some specific reactions and combined according to certain logical thinking. We look forward to the emergence of more reaction modes in the future.