Synthetic Organic Chemistry Research Laboratory, Department of Chemistry, University of Delhi, Delhi-110007, India.
Org Biomol Chem. 2019 Mar 6;17(10):2657-2662. doi: 10.1039/c9ob00128j.
Herein, we report the 6-exo-dig ring closure of ortho-alkynylanilines with readily available aroyl isothiocyanate. An environmentally benign, metal- and base-free, iodine promoted cascade synthesis of highly functionalized (benzo[1,3]thiazin-2-yl)benzimidic acids has been accomplished via in situ generated ortho-alkynylthiourea. The established methodology employs the abundant chemical feedstock of ortho-alkynylanilines and aroyl isothiocyanates and could be applied in the late-stage synthesis of pharmaceutically active 1,3-benzothiazine containing molecules. Furthermore, the discovered protocol exclusively delivers bis (benzo[1,3]thiazin-2-yl)dibenzimidic acid products and preserves the iodo-olefin substitution pattern which can be exploited by further derivatization.
在此，我们报告了邻炔基苯胺与易得的芳基异硫氰酸酯的 6-endo-环合反应。通过原位生成的邻炔基硫脲，在环境友好、无金属和碱的条件下，碘促进了高度官能化的（苯并[1,3]噻嗪-2-基）苯并咪唑酸的级联合成。所建立的方法采用了丰富的化学原料邻炔基苯胺和芳基异硫氰酸酯，可以应用于含有 1,3-苯并噻嗪的药物活性分子的后期合成。此外，该发现的方案专门提供双（苯并[1,3]噻嗪-2-基）二苯并咪唑酸产物，并保留可进一步衍生化的碘-烯烃取代模式。
