Category: 1621-91-6

1621-91-6, 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. 1621-91-6, name is 1H-Pyrazole-3-carboxylic acid, A new synthetic method of this compound is introduced below.

Sulfuric acid (5.8 mL) was added dropwise to a stirred solution of 1H-pyrazole-3-carboxylic acid (1 g, 8.92 mmol) in MeOH (65 mL) at 0 C. After the addition was completed the mixture was allowed to warm to room temperature and stirred for 18 hours. The mixture was concentrated in vacuo and the residue was dissolved in water and basified with NaHCO3 (aq. sat. solution). The mixture was extracted with AcOEt. The organic layer was separated, dried (MgSO4), filtered and the solvents evaporated in vacuo to yield 1H-pyrazole-3-carboxylic acid methyl ester (0.7 g, 62% yield) as a white solid which was used in the next step without further purification.

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1621-91-6,Some common heterocyclic compound, 1621-91-6, name is 1H-Pyrazole-3-carboxylic acid, molecular formula is C4H4N2O2, 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.

General procedure: Into a 1L open reactor was added 500g of carboxylic acid raw material (chemically pure) and stirring was turned on (600 r/min) from the reactorThe bottom is continuously fed with ammonia gas (chemical purity, water content of 5.1% by weight, flow rate of 100 g/min) to the carboxylic acid feed. After the reaction was allowed to proceed for TC hours at the reaction temperature TA, ammonia gas flow was stopped. The contents of the reactor were sampled and subjected to nuclear magnetic proton and elemental analysis to characterize the amide intermediate. Specific reaction conditions and characterization results are shown in Table A-1, Table A-2, Table A-3, Table A-4, Table A-5 and Table A-6. These characterization results show that the amide intermediates obtained have an extremely high purity (above 99%).In this embodiment, the ammonia gas can be directly replaced with waste ammonia gas (from Yangzi Petrochemical Plant, containing approximately50wt% of ammonia gas, the rest were toluene, oxygen, nitrogen, steam, carbon monoxide, and carbon dioxide, and the flow rate of this waste ammonia was 130g/min).

These compound has a wide range of applications. It is believed that with the continuous development of the source of the synthetic route 1H-Pyrazole-3-carboxylic acid, its application will become more common.