A base-promoted cascade reaction of α, β-unsaturated N-tosylhydrazones with o-hydroxybenzyl alcohols: highly regioselective synthesis of N-sec-alkylpyrazoles. Issue 37 (12th September 2019)

• Record Type: Journal Article
• Authors: Chen, Lian-Mei; Zhao, Juan; Xia, An-Jie; Guo, Xiao-Qiang; Gan, Ya; Zhou, Chuang; Yang, Zai-Jun; Yang, Jun; Kang, Tai-Ran
• Is Part Of: Organic & biomolecular chemistry. Volume 17:Issue 37(2019)
• Page Start: 8561
• Page End: 8570
• Publication Date: 2019-09-12
• Subjects: Chemistry, Organic -- Periodicals; Bioorganic chemistry -- Periodicals; Chemistry, Physical organic -- Periodicals; 547
• DOI: 10.1039/c9ob01780a
• Languages: English
• ISSNs: 1477-0520

Abstract

Abstract : An efficient method for the synthesis of N-sec -alkylpyrazoles via a cascade reaction of α, β-unsaturated N -tosylhydrazones with ortho -hydroxybenzyl alcohols has been developed. Abstract : An efficient method for the synthesis of N-sec -alkylpyrazoles through a base-promoted cascade cyclization/Michael addition reaction of α, β-unsaturated N -tosylhydrazones with ortho -hydroxybenzyl alcohols has been developed. The desired products containing di- or triaryl groups at the same carbon atom were afforded in good to excellent yields with excellent regioselectivities (>20 : 1). Moreover, a three-component reaction of ortho -hydroxybenzyl alcohols, α, β-unsaturated N -tosylhydrazones and saturated N -tosylhydrazones also took place to afford pyrazoles in good yields. This reaction offers a new route to triarylmethanes with a simple operation and is applicable for large-scale synthesis.