Free-radical reactions of diazonium salts with α,β-unsaturated carbonyl compounds. A new synthesis of 1,4-diarylpyrazole derivatives |
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Authors: | Attilio Citterio Massimo Ramperti Elena Vismara |
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Abstract: | Free-radical decomposition of diazonium salts catalyzed by titanous or titanous and ferrous salts in the presence of β-substituted α,β-unsaturated carbonyl compounds leads to 1,4-diarylpyrazole derivatives. The reaction occurs via an intermediate azo compound ( 1 ), which can be reduced by the metal salt or can be isolated and hydrogenated to pyrazole derivatives. |
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