School of Chemical Sciences, National Institute of Science Education and Research Bhubaneswar, HBNI, Jatani, Khurda-752050, Odisha, India.
Org Biomol Chem. 2021 Oct 14;19(39):8544-8553. doi: 10.1039/d1ob01151k.
Various functionalised 4-amino-2-(methylthio)quinolines are synthesised through triflic acid-mediated N-heteroannulation of α-functionalized-β-anilino-β-(methylthio)acrylonitriles for the first time. The N-heteroannulation process is highly chemoselective and has mild reaction conditions. However, this process fails in the absence of the β-methylthio group in the acrylonitriles. In addition, a new double N-heteroannulation process is demonstrated to synthesise indolo[3,2-]quinolines from non-heterocyclic precursors. Natural product isocryptolepine is synthesised in four steps from an acyclic precursor.
各种功能化的 4-氨基-2-（甲基硫代）喹啉是通过三氟磺酸介导的α-官能化-β-苯胺基-β-（甲基硫代）丙烯腈的 N-杂环化首次合成的。N-杂环化过程具有高度的化学选择性，且反应条件温和。然而，该过程在丙烯腈中不存在β-甲基硫代基团时失败。此外，还证明了一种新的双重 N-杂环化过程可以从非杂环前体合成吲哚[3,2-]喹啉。天然产物异隐丹参酮可由无环前体经四步合成得到。
