Synthesis of novel π-extended 2,5-disubstituted indolizines and their absorption and fluorescence properties

Author(s)

Arroio, Thais R. ; Bertallo, Camila R. S. ; Leonelo, Laila Ap. D. ; Caires, Franco J. ; Naal, Rose M. Z. G. ; Clososki, Giuliano C.

• Document type: Journal article
• Source: Journal of Molecular Structure; v. 1315, p. 12-pg., 2024-06-17.

Abstract

We report herein the synthesis of novel pi-extended fluorescent 2-aryl-indolizines bearing substituents such as chalcone, styrene and imine groups at the C-5 position of the indolizine. Absorption and fluorescence properties of these 2,5-substituted indolizines were significantly affected by the substitution pattern at the C-5 position, as evidenced by absorption spectra, Stokes shifts and fluorescence measurements. Among the indolizine derivatives, those containing chalcone exhibited a highly notable red shift in their maximum wavelength of fluorescence (lambda em= 650 nm) compared to those containing imine (lambda em= 487 nm) or olefin (lambda em= 543 nm), accompanied by relatively large Stokes shifts (71-171 nm / 2955-6761 cm-1) and fluorescence quantum-yield values from 0.002 to 0.296. All synthesized indolizines demonstrated colorful in solution, while the imine- and olefin-substituted indolizines exhibited fluorescence both in solution and the solid state. The chalcone derivatives showcased the capability to regulate its fluorescence modulation. Although the presence of the carbonyl group extensively suppressed this effect, it was significantly restored upon reduction to the hydroxyl group, demonstrating a promisor "off-on" fluorescent sensors for monitoring oxidative processes within biological systems. (AU)

• FAPESP's process: 20/13962-9 - Synthetic studies aiming at the preparation of new pyridoindois of medicinal interest
• Grantee: Thais Rodrigues Arroio
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 22/05327-7 - Exploring the medicinal chemical space of aromatics with highly selective synthetic tools
• Grantee: Giuliano Cesar Clososki
• Support Opportunities: Regular Research Grants
• FAPESP's process: 14/50867-3 - INCT 2014: National Institute of Science and Technology in Bioanalysis
• Grantee: Marco Aurelio Zezzi Arruda
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 15/03007-1 - Directed functionalization of aromatic indolizines aiming to obtain bioactive substances
• Grantee: Camila Rodrigues de Souza Bertallo
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)