109954-11-2

Upstream product

• 383-63-1 ethyl trifluoroacetate, 
• 103-02-6 acetone phenylhydrazone 
• 367-57-7 1,1,1-Trifluoro-2,4-pentanedione 
• 100-63-0 phenylhydrazine 
• 135351-20-1 (3E)-1,1,1-trifluoro-4-methoxy-pent-3-en-2-one 
• 106578-68-1 (Z)-1,1,1-trifluoro-4-(phenylamino)pent-3-en-2-one 

Downstream Products

• 129585-50-8 3-methyl-1-phenyl-5-(trifluoromethyl)-1H-pyrazole 

Relevant academic research and scientific papers

Pyrazole synthesis under microwave irradiation and solvent-free condition

This paper presents a study of solvent-free reaction conditions using microwave irradiation (MW) to obtain 4,5-dihydro-1H-pyrazoles and dehydrated pyrazoles by the cyclocondensation reaction of 4-alkoxy-1,1,1-trifuoro-3-alken- 2-ones [CF3C(O)CH=C(R1)OR, where R/R1 = Et/H, Me/Me and Me/Ph] with hydrazines [NH2NH-R2, where R2 = CO2Me, Ph, CH2CH2OH]. Some reactions were performed under the same reaction conditions using methanol as solvent. The results obtained using MW equipment for synthesis under solvent-free conditions were also compared with those described in literature for conventional thermal heating and heating with a domestic MW oven. In general, the products furnished by reaction in MW equipment for synthesis presented better yields and shorter reaction times. In addition, it was demonstrated that the reaction temperature altered the formation of products for each hydrazine showing that MW equipment for synthesis is effcient for reacting hydrazines and 4-alkoxy-1,1,1-trifuoro-3- alken-2-ones to procedure the products 4,5-dihydro-1H-pyrazoles and dehydrated pyrazoles.

Improved regioselectivity in pyrazole formation through the use of fluorinated alcohols as solvents: Synthesis and biological activity of fluorinated tebufenpyrad analogs

(Chemical Equation Presented) The preparation of N-methylpyrazoles is usually accomplished through reaction of a suitable 1,3-diketone with methylhydrazine in ethanol as the solvent. This strategy, however, leads to the formation of regioisomeric mixtures of N-methylpyrazoles, which sometimes are difficult to separate. We have determined that the use of fluorinated alcohols such as 2,2,2-trifluoroethanol (TFE) and 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) as solvents dramatically increases the regioselectivity in the pyrazole formation, and we have used this modification in a straightforward synthesis of fluorinated analogs of Tebufenpyrad with acaricide activity.

Microwave assisted regiospecific synthesis of 5-trifluoromethyl-4,5- dihydropyrazoles and - Pyrazoles

(Chemical Equation Presented) The regiospecific synthesis of a series of twelve 5-trifluoromethyl-4,5-dihydropyrazoles and -pyrazoles from the cyclocondesation reaction of 4-alkoxy-1,1,1-trifluoro-3-alken-2-ones [F 3CC(O)CH=C(R1)OR,

Reactions of regioisomeric fluoroalkyl-containing β-aminovinyl ketones with hydrazines

Fluoroalkyl β-alkyl-β-aminovinyl ketones react with hydrazine hydrate to give the respective pyrazoles, and with phenylhydrazine they form a mixture of pyrazoles and 5-hydroxy-Δ2-pyrazolines. Alkyl(aryl) β-fluoroalkyl-β-aminovinylketones do not react with the hydrazines mentioned above. With 2,4-dinitrophenylhydrazine, both types of fluoroalkyl-containing β-aminovinyl ketones give only hydrazones of the corresponding methyl alkyl(aryl) ketones.

Haloacetylated Enol Ethers. 2. Synthesis of 5-Trifluoromethylpyrazoles

1-Methyl-5-(trifluoromethyl)-1H-pyrazoles 2,3 and 4,5-dihydro-1-phenyl-5-(trifluoromethyl)-1H-pyrazol-5-ol 4 were prepared by reaction of 4-alkoxy-1,1,1-trifluoro-3-alken-2-ones 1 and hydrazine, methylhydrazine, and phenylhydrazine, respectively, in good yields.Compound 1 proved to be a versatile building block for the regiospecific construction of pyrazole rings having an 5-trifluoromethyl substituent.

Regioselective Synthesis of Trifluoromethylated Pyrazoles by Selective Protection of Trifluoromethyl-β-diketones

1,1,1-Trifluoropentane-2,4-dione was selectively protected by treatment with pyrrolidine to give 6.The reaction of 6 with arylhydrazines gave 5 exclusively.The structural assignment for 5 was confirmed by quenching the dianion of 8 with ethyl trifluoroace

INVESTIGATION OF THE MECHANISMS OF FORMATION OF HETEROCYCLES BY NMR SPECTROSCOPY

The 13C chemical shifts were obtained for the unstable intermediate products in the reactions of 1,3-diketones R1COCH2COR2 (R1, R2= Me, Et, t-Bu, CF3) with hydrazines NH2NHR3 (R3= H, Me, Ph).The results confirm that they have hydroxypyrazoline, hydrazone, dihydroxypyrazoline, and ketohydroxyhydrazine structures.It was shown that 13C NMR spectroscopy can be used for analysis of the complex nonequilibrium reaction mixtures.