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

S Fustero, R Román, JF Sanz-Cervera…

Index: Fustero, Santos; Roman, Raquel; Sanz-Cervera, Juan F.; Simon-Fuentes, Antonio; Cunat, Ana C.; Villanova, Salvador; Murguia, Marcelo Journal of Organic Chemistry, 2008 , vol. 73, # 9 p. 3523 - 3529

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Citation Number: 135

Abstract

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 ...