Synthesis of imidazole-fused pentacyclic pyrrolo[3,4-c]coumarins via base-promoted rearrangement of coumarin-substituted N-heterocyclic carbene precursors

Karataş M. O., Özdemir N., Küçükbay H.

NEW JOURNAL OF CHEMISTRY, vol.48, no.38, pp.16676-16682, 2024 (SCI-Expanded)

  • Publication Type: Article / Article
  • Volume: 48 Issue: 38
  • Publication Date: 2024
  • Doi Number: 10.1039/d4nj03146f
  • Journal Name: NEW JOURNAL OF CHEMISTRY
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Biotechnology Research Abstracts, Chemical Abstracts Core, Chimica, Compendex, DIALNET
  • Page Numbers: pp.16676-16682
  • Inonu University Affiliated: Yes

Abstract

Pentacyclic pyrrolocoumarin scaffolds are unique structural motifs that form the backbone of many bioactive compounds. Herein, we report the first-time synthesis of imidazole-fused pentacyclic pyrrolo[3,4-c]coumarin derivatives (2) through the stoichiometric reaction between coumarin-substituted N-heterocyclic carbene (NHC) precursors (1) and Pd(OAc)(2), in the presence of an external base. Control experiments revealed that the base-promoted rearrangement of the NHC precursors yields N-(alkyl)aniline-substituted pyrrolo[3,4-c]coumarin derivatives (3), wherein the imidazole ring is opened. Additionally, the formation of 2via the reaction of 3 and Pd(OAc)(2 )indicated that the formation of pentacyclic pyrrolo[3,4-c]coumarin occurs via the base-promoted rearrangement product of NHC precursors.