Synthesis of 4-chalcogenyl pyrazoles via electrophilic chalcogenation/cyclization of α, β-alkynic hydrazones. Issue 9 (25th February 2020)

• Record Type: Journal Article
• Authors: Yu, Xinzhang; Shang, Yu-Zhu; Cheng, Yu-Fei; Tian, Jun; Niu, Yulan; Gao, Wen-Chao
• Is Part Of: Organic & biomolecular chemistry. Volume 18:Issue 9(2020)
• Page Start: 1806
• Page End: 1811
• Publication Date: 2020-02-25
• Subjects: Chemistry, Organic -- Periodicals; Bioorganic chemistry -- Periodicals; Chemistry, Physical organic -- Periodicals; 547
• DOI: 10.1039/d0ob00050g
• Languages: English
• ISSNs: 1477-0520

Abstract

Abstract : 4-Chalcogenyl pyrazoles, including the 4-sulfenyl celecixib derivative, are accessed through cyclization of α, β-alkynic hydrazones induced by S-electrophiles prepared in advance or generated in situ . Abstract : A facile method for the synthesis of 4-chalcogenylated pyrazoles has been developed via electrophilic chalcogenation/cyclization of α, β-alkynic hydrazones. The cyclization of α, β-alkynic aldehyde hydrazones could be induced by using either sulfenyl chloride or the S-electrophiles generated in situ from the reaction of NCS and arythiol. The developed method was successfully applied to the synthesis of the sulfenyl analogue of celecoxib.