Research Article
DMAP Catalysed Selective Synthesis of Thiopyrano[2,3-B]Quinoline Derivatives through Cascade Protocol
Author(s): Sreenivas Avula* and Srikanth Reddy Narra
A convenient and rapid synthesis of hitherto unknown Thiopyrano[2,3-b]quinoline derivatives (3) from β-aroyl-thioacetanilides (1) and 2-chloro quinoline-3-carbaldehyde (2) in the presence of simple organic bases. Initially, β-aroyl-thioacetanilides undergo condensation with 2-chloro quinoline-3-carbaldehyde (2) and followed by intramolecular cyclization (SNAr) to obtained the Thiopyrano[2,3-b]quinoline derivatives (3a-3o). For this transformation, we have found that DMAP is the best catalyst for chemo-selective synthesis of Thiopyrano[2,3-b]quinolones derivatives in high yields. All the final compounds were well characterized by 1H NMR, 13C NMR and HRMS, further confirmed by single X-ray crystallography for 3a and 4a compounds... Read More»