Synthesis of Chromeno[4,3-b]pyrrol-4(1H)-ones, from beta-Nitroalkenes and 4-Phenylaminocoumarins, under Solventl-free Conditions

IGLESIAS, B. A.; SILVEIRA, C. C.; PADILHA, G.; KAUFMAN, T. S.; BACK, D. F.

ChemistrySelect

Wiley

Año: 2017 vol. 2 p. 1297 - 1304

2365-6549

A new approach toward chromeno[4,3-b]pyrrol-4(1H)-ones, by annulation of 4-phenylaminocoumarins with £]-nitroalkenes, is reported and its conditions were optimized. The transformations under the fine-tuned conditions took place under promotion by TsOH.H2O, in the absence of solvent. The scope and limitations of the process were explored, by systematic modification of two diversification points. A reaction mechanism, triggered by a Michael addition of the nitrogen moiety of the 4-phenylaminocoumarins to the £]-nitroalkene, was also proposed. Further functionalization of a selected tricycle was performed; the photophysical (UV and fluorescence spectra; 1O2 generation) and electrochemical (cyclic voltammetry) properties of some heterocycles were studied.