有机化学 ›› 2024, Vol. 44 ›› Issue (9): 2832-2840.DOI: 10.6023/cjoc202404017 上一篇    下一篇

研究论文

硫氰酸铵促进的[3+3]环化反应合成5-芳基吡唑并[1,5-a]嘧啶

李龙龙a, 何欣悦a, 周龙生a, 曲亨通a, 冯承涛a,*(), 徐坤b,*()   

  1. a 安徽中医药大学药学院 合肥 230012
    b 北京工业大学化学与生命科学学院 北京 100124
  • 收稿日期:2024-04-11 修回日期:2024-05-07 发布日期:2024-05-23
  • 通讯作者: 冯承涛, 徐坤
  • 基金资助:
    安徽省自然科学基金(2008085MB50); 及安徽省高校自然科学研究重点(KJ2021A0598)

NH4SCN-Promoted Formal [3+3] Annulation for the Synthesis of 5-Arylated Pyrazolo[1,5-a]pyrimidines

Longlong Lia, Xinyue Hea, Longsheng Zhoua, Hengtong Qua, Chengtao Fenga(), Kun Xub()   

  1. a School of Pharmacy, Anhui University of Chinese Medicine, Hefei 230012
    b College of Chemistry and Life Science, Beijing University of Technology, Beijing 100124
  • Received:2024-04-11 Revised:2024-05-07 Published:2024-05-23
  • Contact: Chengtao Feng, Kun Xu
  • Supported by:
    Anhui Provincial Natural Science Foundation(2008085MB50); Education Bureau of Anhui Province(KJ2021A0598)

报道了硫氰酸铵促进的3-氨基吡唑与肉桂醛或肉桂醇的[3+3]环加成反应, 该方法为5-芳基化吡唑并[1,5-a]嘧啶化合物的合成提供了一种实用的合成途径, 反应具有良好的官能团兼容性. 值得注意的是, 在I2O5存在下, 硫氰酸铵作为氰基源, 与肉桂醛反应生成瞬态的氰醇分子, 能够将后续的反应中心从肉桂醛的醛基转移到烯基, 从而实现与现有报道相反的区域选择性.

关键词: 串联环化, 高价碘, 区域选择性, 吡唑并[1,5-a]嘧啶, 肉桂醛

A formal [3+3] annulation of 3-aminopyrazoles with cinnamaldehydes or cinnamyl alcohols mediated by NH4SCN has been developed. This protocol provides a practical route to construct 5-arylated pyrazolo[1,5-a]pyrimidines with high functional group tolerance. The use of NH4SCN as the cyanide anion surrogate allows the transient generation of cyanohydrin, which shifts the reactive center within cinnamaldehydes from formyl group to alkene group to realize an opposite regiocontrol comparing with previous reports.

Key words: tandem cyclization, hypervalent iodine, regioselectivity, pyrazolo[1,5-a]pyrimidine, cinnamaldehyde