Researchers who often do experiments know that organic synthesis is a process of preparing more complex target molecules from simple raw materials through one or more chemical reactions. Generally, it requires fewer steps, and cheap raw materials. 2075-46-9, name is 4-Nitro-1H-pyrazole, A new synthetic method of this compound is introduced below., Safety of 4-Nitro-1H-pyrazole
At 0 C,Concentrated sulfuric acid (50 ml)Was slowly added to the pyrazole (14 g)Concentrated nitric acid (9.2 ml) was then slowly added to the mixture, and the reaction was stirred at 60 C for 1.5 hours.After completion of the reaction, the reaction solution was slowly added to an appropriate amount of ice water, and the resulting white solid was separated by filtration, and the resulting solid was allowed to dry in air,The filtrate was extracted with ethyl acetate (30 ml x 3)The organic phase liquid was then rotary evaporated and dried, and finally the two parts of the solid were combined to give the compound 1a,1a (6 mmol) was dissolved in dry DMF (6 ml)Then, K2CO3 (9 mmol), methyl iodide (12 mmol),The reaction was stirred at room temperature for 16 hours.After completion of the reaction, the reaction solution was extracted with water and ethyl acetate (25 ml x 3)The organic phase was then removed with anhydrous magnesium sulfate.Finally, the organic phase was evaporated under vacuum to dryness to give a crude product,And purified by silica gel column chromatography to obtain Compound 2a.Compound 2a (2 mmol) was dissolved in absolute ethanol (5 ml)Then, palladium carbon (0.04 g) was added successively thereto,Hydrazine hydrate (1 ml), and the reaction solution was stirred at 80 C for 10 minutes.After completion of the reaction, the reaction solution was filtered to remove palladium carbon, and the filtrate was evaporated to dryness under reduced pressure in vacuo to give Compound 3a.Bromoacetic acid (2 mmol) was dissolved in dichloromethane (15 ml), and HOBt (2 mmol) was added thereto successively,EDC (2 mmol), and the reaction solution was stirred at room temperature for 30 minutes,The resulting 3a was then added and the reaction was stirred at room temperature for 12 hours.After completion of the reaction, the reaction solution was extracted with water and dichloromethane (30 ml x 3)Finally, the organic phase liquid was evaporated to dryness and the resulting crude product was purified by silica gel column chromatography to obtain Compound 4a.The resulting compound 4a, indole (2 mmol), NaH (2.4 mmol) was added to dry DMF (10 mL)The reaction solution was stirred at room temperature for 12 hours, and then quenched by adding saturated brine to the reaction.The resulting reaction mixture was extracted with saturated brine and ethyl acetate (30 mL x 3)The organic phase was then removed with anhydrous magnesium sulfate.Finally, the organic phase was evaporated under vacuum to dryness to give a crude product,And purified by silica gel column chromatography to obtain the final compound 5a to give a red solid powder in a yield of 60%
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.