Ultrasound-assisted synthesis, photophysical behaviour and single crystal X-ray analysis of highly functionalized prenylarenes

A rapid, ultrasound assisted base-catalysed metal free synthesis of a novel series linear prenylarenes 17 incorporated with donor-acceptor functionalities is described via carbanion-induced ring transformation of 4-amino-6-aryl-3-cyano-2H-pyran-2-ones 15 with 6-methylhept-5-en-2-one 16 at room temperature with high yields. Notably, all of the synthesised prenylarenes exhibited blue fluorescence in the 406- 468 nm region. The stokes shift, optical band gap, and quantum yield of compounds 17a-17l were computed using their absorption and emission spectra. A significant positive solvatochromic effect was observed, and concentration studies revealed the non-aggregating behaviour of synthesised prenylarenes. Single crystal X-ray diffraction analysis of 17d revealed that crystal belongs to triclinic system with P-1 space group with twisted phenyl rings.(c) 2022 Elsevier B.V. All rights reserved.

Automated summary

A rapid, metal-free synthesis of a novel series of linear prenylarenes 17 was achieved using ultrasound-assisted base-catalysis, with high yields obtained through carbanion-induced ring transformation. The synthesised prenylarenes exhibited blue fluorescence, and solvatochromic effect and non-aggregation behavior were observed.