Natural Products and Medicinal Chemistry Division, CSIR-Indian Institute of Integrative Medicine, Canal Road, Jammu, 180001, Jammu and Kashmir, India.
Academy of Scientific and Innovative Research, Ghaziabad, 201002 (UP), India.
Chem Asian J. 2022 Nov 16;17(22):e202200778. doi: 10.1002/asia.202200778. Epub 2022 Oct 1.
A facile, sustainable and eco-friendly protocol has been developed for the halogenation of various heterocycles using TBAX (TBAI/TBAB/TBACl) as halogenating agent, which afforded the products in 90-95% isolated yields. The reaction proceeds with low-cost TBAX and uses greener conditions like EtOH as a solvent and microwave as an alternative energy source for reaction. This protocol has been applied on pyrazoles and extended to different heterocycles like 7-azaindole, indazole, indole and 2-phenylimidazo[1,2-α]pyridines. The gram-scale iodination reaction has also been successfully performed by optimizing conventional heating conditions, which demonstrates its potential applicability in organic synthesis. Further these halogenated pyrazoles have been utilized for different coupling reactions including formation of arylated, alkynylated and sulfenated pyrazoles. However, TBAF mediated fluorination did not work.
已经开发出一种简便、可持续且环保的方法，使用 TBAX（TBAI/TBAB/TBACl）作为卤化剂，可将各种杂环化合物卤化，产率为 90-95%。该反应使用低成本的 TBAX，并且采用更环保的条件，如乙醇作为溶剂，微波作为反应的替代能源。该方法已应用于吡唑类化合物，并扩展到其他杂环化合物，如 7-氮杂吲哚、吲唑、吲哚和 2-苯基咪唑并[1,2-α]吡啶。通过优化常规加热条件，已成功进行克级碘化反应，这表明其在有机合成中具有潜在的适用性。此外，这些卤化吡唑类化合物已用于各种偶联反应，包括芳基化、炔基化和磺化吡唑的形成。然而，TBAF 介导的氟化反应不起作用。
