Continuous-flow synthesis of 3,5-disubstituted pyrazoles via sequential alkyne homocoupling and Cope-type
Sándor B Ötvös1,2,3, Ádám Georgiádes1, Dániel Ozsvár1
1Institute of Pharmaceutical Chemistry, University of Szeged, Interdisciplinary Excellence Center Eötvös u. 6 H-6720 Szeged Hungary otvossandor@pharm.u-szeged.hu fulop@pharm.u-szeged.hu +36-62-545-705 +36-62-545-768 +36-62-545-562.
Abstract:
A flow chemistry-based approach is presented for the synthesis of 3,5-disubstituted pyrazoles via sequential copper-mediated alkyne homocoupling and Cope-type hydroamination of the intermediary 1,3-diynes in the presence of hydrazine as nucleophilic reaction partner. The proposed multistep methodology offers an easy and direct access to valuable pyrazoles from cheap and readily available starting materials and without the need for the isolation of any intermediates.
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