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Prop-2-enylidene indolones substituted with L-amino acid esters are obtained in good to excellent yields in a consecutive three-component cyclocarbopalladation, Sonogashira coupling, and Michael addition sequence. While primary L-amino acid esters furnish a mixture of E,E- and E,Z-configurated diastereomers, L-proline methyl ester selectively and exclusively furnishes the E,E-isomer. As already discovered for other 3-aminoprop-2-enylidene indolones, the drop-casted films of all representatives display pronounced aggregation-induced orange-red fluorescence with large Stokes shifts, while all chromophores are nonemissive in solution.

1. Chalcones are structural analogues of benzalacetophenone (BAP). Several derivatives have been identified in plants and anticarcinogenic and anti-inflammatory properties were attributed to the compounds, probably related to their direct antioxidant activity or stimulatory effects on the expression of endogenous defence enzymes like hemeoxygenase-1 (HO-1). HO-1 expression is triggered by the Nrf2-Keap1 signalling pathway, initiated by the addition of chalcones to thiol groups of Keap1 via Michael-type reaction. 2. The present study used a model system estimating the reactivity of different synthetic chalcones and other α,β-unsaturated carbonyl compounds with thiols and compared the chemical reactivity with the biological activity, measured by HO-1 expression in human dermal fibroblasts. 3. Chemical reactivity with the thiol group of N-acetylcysteine was determined with 5,5'-dithiobis-(2-nitrobenzoic acid) and followed chemical principles of structure-reactivity relationship. Most reactive were sulforaphane, dimethylfumarate, chalcone 3 ((2E)-1-phenyl-3-pyrimidin-2-ylprop-2-en-1-one) and chalcone 7 (1,3-diphenylprop-2-yn-1-one). This result demonstrates that α,β-unsaturated carbonyl derivatives react with thiols differently. All compounds were also biologically active; however, expression of HO-1 was not only related to the chemical reactivity but also to the lipophilicity of the molecules which likely affected transmembrane uptake. Most efficient inducers of HO-1 expression were BAP, 4-hydroxynonenal and chalcone 1 (4-[(1E)-3-oxo-3-phenylprop-1-en-1-yl]benzonitrile), chalcone 5 ((2E)-1-phenyl-3-[4-(trifluoromethyl)-phenyl]prop-2-en-1-one) and chalcone 7.

In a consecutive three-component cyclocarbopalladation, Sonogashira coupling, Michael addition sequence 4-aminopropenylidene indolones, i.e., terminally fixed push-pull chromophores, are obtained in yields as high as 99%. Most remarkable, however, is the pronounced orange red solid state fluorescence displaying large Stokes shifts of these merocyanines, in particular, since all chromophores are nonfluorescent in solution.

Based upon a twofold bromine―lithium exchange with 2,5-dibromo thiophene and sequential trapping of the dilithio intermediate, organo zinc halides were generated in situ and subsequently transformed by Negishi cross-coupling to unsymmetrically substituted thiophenes in a one-pot fashion. Application of this novel sequence to diiodo(hetero)arenes quickly furnishes highly interesting building blocks for materials science applications.

Double bromine-lithium exchange and sequential trapping of the dilithio intermediate with different electrophiles gives rise to the formation of unsymmetrically substituted (hetero)arenes in a one-pot fashion.

Prop-2-enylidene indolones substituted with L-amino acid esters [(IV), (V), and (VII)] are synthesized using a cyclocarbopalladation, Sonogashira coupling, and Michael addition sequence.

The title compounds (IV), (VI), (VIII), and (IX) are intensely red or yellow emissive in the solid state and show large Stokes shifts.

A novel consecutive three-component coupling-enamine addition synthesis gives access to three types of diene merocyanines in a selective fashion and in good yields. Moreover, all these push-pull systems are intensely red or yellow emissive in the solid state and display large Stokes shifts.

All products display an intense solid-state fluorescence, yet they are completely nonemissive in solution.