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Upstream product

• 766-96-1 4-bromo-1-ethynylbenzene 
• 1514-82-5 2-bromo-3,3,3-trifluoropropene 
• 25939-12-2 4-bromo-N-phenylbenzohydrazonoyl chloride 
• 100-63-0 phenylhydrazine 
• 18931-61-8 4,4,4-trifluoro-1-(4-bromophenyl)butane-1,3-dione 
• 59-88-1 phenylhydrazine hydrochloride 

Relevant academic research and scientific papers

Regioselective Synthesis of 5-Trifluoromethylpyrazoles by [3 + 2] Cycloaddition of Nitrile Imines and 2-Bromo-3,3,3-trifluoropropene

A general and practical method for the synthesis of 5-trifluoromethylpyrazoles is reported that occurs by the coupling of hydrazonyl chlorides with environmentally friendly and large-tonnage industrial feedstock 2-bromo-3,3,3-trifluoropropene (BTP). This exclusively regioselective [3 + 2] cycloaddition of nitrile imines and with BTP is catalyst-free and operationally simple and features mild conditions, high yields, gram-scalable, a broad substrate scope, and valuable functional group tolerance. Significantly, our method has been applied for the synthesis of the key intermediate of an active agonist of sphingosine 1-phosphate receptor.

5-trifluoromethyl substituted pyrazole derivative, synthesis method and application thereof

The invention discloses a 5-trifluoromethyl substituted pyrazole derivative, a synthesis method and application thereof, and belongs to the technical field of substituted pyrazole derivatives. The synthesis method comprises the following steps of: adding chloroaldehyde hydrazone, 2-bromo-3, 3, 3-trifluoropropene, alkali and an organic solvent into a reactor, carrying out stirring reaction, and carrying out after-treatment on the reaction product to obtain the 5-trifluoromethyl substituted pyrazole derivative. According to the synthesis method, no catalyst is used, and the used raw materials are non-toxic, cheap and easily available; the reaction is good in functional group adaptability, wide in substrate adaptability, high in product yield and good in regioselectivity. Moreover, the synthesis method is simple and safe to operate, mild in reaction condition and insensitive to water and air, and has a good industrial application prospect.

Selective, Metal-Free Approach to 3- or 5-CF3-Pyrazoles: Solvent Switchable Reaction of CF3-Ynones with Hydrazines

A detailed study of the reaction of trifluoroacetylated acetylenes and aryl (alkyl) hydrazines was performed, aimed to the regioselective synthesis of 3- or 5-trifluoromethylated pyrazoles. It was found that the regioselectivity of reaction depends dramatically on the solvent nature. Highly polar protic solvents (hexafluoroisopropanol) favor the formation of 3-trifluoromethylpyrazoles. In contrast, when the reaction was performed in polar aprotic solvents (DMSO), the formation of their 5-CF3-substituted isomers was preferentially observed. Alternatively, the regioselective assembly of 3-CF3-substituted pyrazoles can be performed via two-step one-pot procedure. The reaction of trifluoromethylated ynones with aryl (alkyl) hydrazines in the presence of acidic catalysts leads to formation of the corresponding hydrazones. The latter can be smoothly transformed into 3-CF3-pyrazoles by treatment with a base. This solvent-switchable procedure was used for the preparation of such important drugs as Celebrex and SC-560 as well as their isomers in gram scale. The possible reaction mechanism is discussed.

Synergic effects of ionic liquid and microwave irradiation in promoting trifluoromethylpyrazole synthesis

The synthesis of 5-trifluoromethyl-1-phenyl-1H-pyrazoles from the reactions of 4-alkoxy-1,1,1-trifluoro-3-alken-2-ones [CF3C(O)CH=C(R 1)OR, where R = Me, Et; R1= H, Me, Bu, i-Bu, Ph, 4-MeC6H4, 4-FCsu

Highly regioselective synthesis of 1-aryl-3,4,5-substituted pyrazoles

A highly regioselective synthesis of 1-aryl-3,4,5-substituted pyrazoles based on the condensation of 1,3-diketones with arylhydrazines is described. The reaction proceeds at room temperature in N,N-dimethylacetamide and furnishes pyrazoles in 59-98% yield