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Updated: Feb 28, 2026

Facile Preparation of 4-Substituted Quinazoline Derivatives
Published on: February 15, 2016
Synthesis of a Highly Fluorescent Quinoxalino[2,3-b]quinoxaline Polycyclic Derivative via Intramolecular Michael
Giacomo Picci1, Jessica Milia1, Vito Lippolis1
1Department of Chemical and Geological Science, University of Cagliari, S.S. 554 Bivio per Sestu, 09042 Monserrato, CA, Italy.
Abstract:
In the presence of TBAOH, bis-indolylsquaramide (1) converts into the highly emissive, novel bis(3H-pyrrolo[1,2,3-de]quinoxaline) exa-cyclic derivative 2. This compound was fully characterized in solution and the solid state, with emission properties supported by DFT calculations. Derivative 2 exhibits high quantum yield in solution with aggregation-induced quenching, and a large spectral shift between solid state and solution. Reaction conditions were optimized, and a mechanism involving a double intramolecular Michael addition triggered by deprotonation, oxidation and photodecarbonylation was proposed on the basis of DFT calculations and LC-MS measurements. In addition to reporting a novel, highly π-conjugated emissive compound, this manuscript highlights an unprecedented squaramide reactivity under basic conditions, resulting in the first example of intramolecular quinoxaline moiety formation from a squaramide derivative.
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