Jensen reaction

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The Jensen reaction , also Jensen acylation , is a name reaction from organic chemistry . The reaction is named after its discoverer Bror Skytte Jensen . It is used to prepare 4-acyl-5-pyrazolones / 4-acylpyrazol-5-ols ( 3 , see figure) or 4-acyl-5-isoxazolones from pyrazolones ( 1 ) or from isoxazolones and carboxylic acid chlorides ( 2 ) in the presence of calcium hydroxide Ca (OH) 2 . The preferred solvent is 1,4-dioxane .

Reaction scheme of the Jensen reaction

Individual evidence

  1. ↑ Bror Skytte Jensen: The synthesis of 1-phenyl-3-methyl-4-acyl-pyrazolones-5 . In: Acta Chem. Scand . tape 13 , no. 8 , 1959, pp. 1668–1670 ( actachemscand.org [PDF; accessed June 8, 2015]).