Synthesis 2019; 51(11): 2293-2304
DOI: 10.1055/s-0037-1611747
paper
© Georg Thieme Verlag Stuttgart · New York

Synthesis of 4-Organoselanyl-1H-pyrazoles: Oxone®-Mediated Electrophilic Cyclization of α,β-Alkynyl Hydrazones by Using Diorganyl Diselenides

a   Laboratório de Síntese Orgânica Limpa – LASOL, CCQFA, Universidade Federal de Pelotas – UFPel, P. O. Box 354, 96010-900, Pelotas, RS, Brazil   Email: gelson_perin@ufpel.edu.br
,
Patrick C. Nobre
a   Laboratório de Síntese Orgânica Limpa – LASOL, CCQFA, Universidade Federal de Pelotas – UFPel, P. O. Box 354, 96010-900, Pelotas, RS, Brazil   Email: gelson_perin@ufpel.edu.br
,
Daniela H. Mailahn
a   Laboratório de Síntese Orgânica Limpa – LASOL, CCQFA, Universidade Federal de Pelotas – UFPel, P. O. Box 354, 96010-900, Pelotas, RS, Brazil   Email: gelson_perin@ufpel.edu.br
,
Márcio S. Silva
a   Laboratório de Síntese Orgânica Limpa – LASOL, CCQFA, Universidade Federal de Pelotas – UFPel, P. O. Box 354, 96010-900, Pelotas, RS, Brazil   Email: gelson_perin@ufpel.edu.br
,
Thiago Barcellos
b   Laboratório de Biotecnologia de Produtos Naturais e Sintéticos, Universidade de Caxias do Sul – UCS, Caxias do Sul, RS, Brazil
,
Raquel G. Jacob
a   Laboratório de Síntese Orgânica Limpa – LASOL, CCQFA, Universidade Federal de Pelotas – UFPel, P. O. Box 354, 96010-900, Pelotas, RS, Brazil   Email: gelson_perin@ufpel.edu.br
,
a   Laboratório de Síntese Orgânica Limpa – LASOL, CCQFA, Universidade Federal de Pelotas – UFPel, P. O. Box 354, 96010-900, Pelotas, RS, Brazil   Email: gelson_perin@ufpel.edu.br
,
Claudio Santi
c   Department of Pharmaceutical Sciences, University of Perugia, Via del Liceo 1, Perugia, Italy
,
Juliano A. Roehrs
d   Instituto Federal de Educação Ciência e Tecnologia Sul-rio-grandense, IFSul, 96015360, Pelotas, RS, Brazil
› Author Affiliations
The authors are grateful to Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) and Fundação de Amparo à Pesquisa do Estado do Rio Grande do Sul (FAPERGS) for financial support (Grant number: 17/2551-0000987-8). This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior – Brasil (CAPES) (finance Code 001). CNPq is also acknowledged for fellowships to G.P., R.G.J., and E.J.L.
Further Information

Publication History

Received: 17 December 2018

Accepted after revision: 05 February 2019

Publication Date:
14 March 2019 (online)


Abstract

A simple and efficient method for the synthesis of 4‑organoselanyl-1H-pyrazoles has been developed, taking place under metal- and halogen-free conditions. Electrophilic species of selenium were easily generated in situ by the reaction of diorganyl diselenides with Oxone® in ethanol as solvent in an open-flask at 70 °C. These electrophilic selenium species were employed in the selenylation/cyclization of α,β-alkynyl hydrazones, giving the title compounds in moderate to excellent yields. The final species of selenium obtained from the reaction of diphenyl diselenide with Oxone® were characterized by 77Se NMR spectroscopy and high-resolution mass spectrometry (HRMS).

Supporting Information