本研究报告了一种在可见光照射和连续流相结合的情况下,在没有任何外部光催化剂的情况下,在 C3 位置对咪唑并[1,2- a ]吡啶支架进行高度区域选择性光催化 C-H 亚硝基化的方案。该方案涉及温和、安全的条件,对空气和水表现出良好的耐受性,以及出色的官能团相容性和位点选择性,在光催化剂、氧化剂和添加剂的作用下以优异的产率生成各种3-亚硝基咪唑并[1,2- a ]吡啶值得注意的是,由于亚硝基化的强光吸收特性,所提出的亚硝基化反应将发色团NO引入咪唑并[1,2- a ]吡啶支架中,在可见光照射下有效发生,无需任何额外的光催化剂产品。这项研究可以指导未来开发具有广泛潜在应用的绿色有机合成策略的研究。
Iodine-Mediated Difunctionalization of Imidazopyridines with Sodium Sulfinates: Synthesis of Sulfones and Sulfides
作者:Yu-Jing Guo、Shuai Lu、Lu-Lu Tian、En-Ling Huang、Xin-Qi Hao、Xinju Zhu、Tian Shao、Mao-Ping Song
DOI:10.1021/acs.joc.7b02734
日期:2018.1.5
Novel iodine-induced sulfonylation and sulfenylation of imidazopyridines have been described using sodium sulfinates as the sulfur source. This strategy enables highly selective difunctionalization of imidazo[1,2-a]pyridine to access sulfones and sulfides in good yields. A wide range of substrates and functional groups were well-tolerated under optimized conditions. Moreover, control experiments have
已经描述了使用亚磺酸钠作为硫源的新的碘诱导的咪唑并吡啶的磺酰化和亚磺酰化。该策略能够使咪唑并[1,2- a ]吡啶高度选择性地进行双官能化,从而以高收率获得砜和硫化物。在最佳条件下,各种底物和官能团均具有良好的耐受性。此外,已经进行了对照实验,表明了反应机理中涉及的自由基途径。
Metal-Free Regioselective Alkylation of Imidazo[1,2-a]pyridines with N-Hydroxyphthalimide Esters under Organic Photoredox Catalysis
A visible-light-induced direct C–H alkylation of imidazo[1,2-a]pyridines has been developed. It proceeds at room temperature by employing inexpensive Eosin Y as a photocatalyst and alkyl N-hydroxyphthalimide (NHP) esters as alkylationreagents. A variety of NHP esters derived from aliphatic carboxylicacids (primary, secondary, and tertiary) were tolerated in this protocol, giving the corresponding
Electrochemical Oxidative Regioselective C–H Cyanation of Imidazo[1,2-<i>a</i>]pyridines
作者:Ting Cui、Yanling Zhan、Changhui Dai、Jun Lin、Ping Liu、Peipei Sun
DOI:10.1021/acs.joc.0c03026
日期:2021.11.19
Electrochemical oxidative regioselective C–H cyanation of imidazo[1,2-a]pyridines was developed using readily available TMSCN as the cyano source. The KH2PO4/K2HPO4 buffer was essential for this transformation. This protocol was compatible with a broad range of substituted imidazo[1,2-a]pyridines and provided the C3 cyanated products in moderate to excellent yields.
咪唑并[1,2- a ]吡啶的电化学氧化区域选择性C-H氰化是使用现成的TMSCN作为氰基源开发的。KH 2 PO 4 /K 2 HPO 4缓冲液对于这种转化是必不可少的。该方案与多种取代的咪唑并[1,2- a ]吡啶兼容,并以中等至优异的产率提供C3氰化产物。
Micellar Catalysis: Visible‐Light Mediated Imidazo[1,2‐
<i>a</i>
]pyridine C—H Amination with
<i>N</i>
‐Aminopyridinium Salt Accelerated by Surfactant in Water
A light-promoted metal-free protocol for the amination of imidazo[1,2-a]pyridines with N-aminopyridinium salt by the assistance of surfactants in water was reported, charactering mild and environmentally benign conditions, as well as great functional group tolerance. Micelles with negatively charged polar surface and hydrophobic core formed from sodium dodecyl sulfate serve as an ideal medium for visible-light
报道了在水中表面活性剂的辅助下咪唑并[1,2- a ]吡啶与N-氨基吡啶鎓盐胺化的光促进无金属方案,具有温和和环境友好的条件,以及良好的官能团耐受性. 具有带负电荷的极性表面和由十二烷基硫酸钠形成的疏水核的胶束是可见光介导的阳离子吡啶盐和咪唑并[1,2- a ]吡啶在水相中发生自由基反应的理想介质。带正电荷的N-氨基吡啶鎓与带负电荷的胶束表面之间的静电相互作用在该方法中具有重要意义。
Ultrasound-Promoted and Base-Mediated Regioselective Bromination of Imidazo[1,2-a]pyridines with Pyridinium Tribromide
作者:Qing-Wen Gui、Hongmei Jiang、Dingyi Guo、Yixin Zhang、Qin-Peng Shen、Shiyun Tang、Junheng You、Yi Huo、Huixian Wang
DOI:10.1055/s-0040-1707856
日期:2020.9
Abstract By using pyridinium tribromide as the bromo source, an efficient and practical protocol for the synthesis of C3-brominated imidazo[1,2-a]pyridines through ultrasound-promoted and Na2CO3-mediated regioselective bromination of imidazo[1,2-a]pyridines has been developed. This method effectively avoids the use of metal catalysts and harsh reaction conditions, and shows attractive characteristics
摘要 通过使用三溴化吡啶鎓作为溴源,通过超声促进和Na 2 CO 3介导的咪唑并[1,2-]区域选择性溴化合成C3-溴化的咪唑并[1,2- a ]吡啶的有效而实用的方案。已经开发了α ]吡啶。该方法有效地避免了使用金属催化剂和苛刻的反应条件,并显示出引人注目的特性,例如操作简便,宽范围的基材范围以及良好至优异的收率,易于规模化生产和高能源效率。