Synthesis of indazoles from 2-formylphenylboronic acids
Vitalii V Solomin1,2, Alberts Seins1,2, Aigars Jirgensons1,2
1Latvian Institute of Organic Synthesis Aizkraukles 21 Riga LV-1006 Latvia aigars@osi.lv.
Abstract:
A method for the synthesis of indazoles was developed which involves a copper(ii) acetate catalysed reaction of 2-formylboronic acids with diazadicaboxylates followed by acid or base induced ring closure. Hydrazine dicarboxylates were also shown as competent reaction partners for the synthesis of indazoles, however, they required a stoichiometric amount of copper(ii) acetate for the C-N bond formation step. The transformation can be efficiently performed as a two step-one pot procedure to give a range of 1N-alkoxycarbonyl indazoles.
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