Nitrogen's reactivity of various 3-alkoxypyrazoles

Sandrine Guillou (1) , Frédéric J. Bonhomme (1) , Yves Louis Janin (1)

1 Chimie Organique

Our current interest in the design of original chemical libraries featuring a pyrazole nucleus led us to focus on the chemistry of the 3-alkoxy-5-methylpyrazoles we have recently made readily available. With in mind the preparation of an array of the less accessible 1-arylpyrazol-3-ones, the present report describes the respective nitrogen's reactivity of various 3-alkoxypyrazoles toward arylation reaction, using arylboronic acids, as well as alkylation reactions using methyl iodide or benzylbromide. The structure assignments of the isomers obtained were achieved using long distance 15N-1H NMR correlation measurements or by the recourse to unambiguous synthetic pathways.

Keywords: 3-Alkoxypyrazole; N-Arylation; N-Alkylation

Domains: Chemical Sciences; Organic chemistry

Sandrine Guillou, Frédéric J. Bonhomme, Yves Louis Janin. Nitrogen's reactivity of various 3-alkoxypyrazoles. Tetrahedron, 2009, 65 (13), pp.2660-2668. ⟨10.1016/j.tet.2009.01.099⟩. ⟨pasteur-00370354⟩