Groebke–Blackburn–Bienaymé multicomponent reaction coupled with unconventional Pictet–Spengler cyclization for the synthesis of imidazo[4, 5‐b]pyridine fused polycyclic heterocycles. (13th January 2022)

• Record Type: Journal Article
• Authors: Singh, Rahul; Kumar, Ravinder; Kaur, Manpreet; Patil, Madhuri T.; Sahoo, Subash Chandra; Salunke, Deepak B.
• Is Part Of: Journal of heterocyclic chemistry. Volume 59:Number 6(2022)
• Page Start: 1007
• Page End: 1015
• Publication Date: 2022-01-13
• Subjects: Heterocyclic compounds -- Periodicals; 547.59
• DOI: 10.1002/jhet.4438
• Languages: English
• ISSNs: 0022-152X

Abstract

Abstract: A diverse library of fused tetracyclic and pentacyclic imidazo[4, 5‐ b ]pyridine scaffolds was synthesized using an unconventional strategy, involving Groebke–Blackburn–Bienaymé (GBB) multicomponent reaction coupled with Pictet–Spengler (PS) cyclization. The reaction strategy involves the use of 2‐aminoazine, aldehyde, and 1, 1, 3, 3‐tetramethyl butyl isocyanide in the GBB reaction followed by the dealkylation to generate a free amine, which on PS cyclization with another aldehyde generated a fused polycyclic heterocycle. A small set of 15 diverse polycyclic heterocycles were synthesized and their structures were confirmed by 1 H NMR, 13 C NMR, and mass spectrometric analyses. In addition, a single‐crystal X‐ray diffraction of one of the library members established the three‐dimensional structure of the polycyclic skeleton. Abstract :