Aerobic Dimerization of Ethyl 4-Thienyl-3-ketobutanoate toward a Modifiable Photochromic Diarylethene Precursor

Abstract

A unique chemical transformation, the base-induced aerobic dimerization of ethyl 4-(2,5-dimethylthiophen-3-yl)-3-ketobutanoate leading to photochromic diarylethene with a 4-hydroxy-4-methylcyclopent-2-ene-1-one as an ethene bridge, is described. This compound is easily subjected to various chemical modifications and can be used as a new diarylethene precursor to produce photoactive compounds with desired properties and functions.

Turn‐On Fluorescent Photochromic Disulfonylarylthiophenes: Effect of Sulfone Groups on Fluorescence and Conversion

“…When a solution of 2 in EA was irradiated with UV (312 nm), the color of the solution turned yellow, and an absorption band at 487 nm was observed in the UV/Vis spectrum (Figure ). This result can be seen as a change from the open structure of 2 (o‐ 2 ) to its closed structure (c‐ 2 ) found in common diarylethene photochromic materials . The absorption band of c‐ 2 was blue shifted by 51 nm compared to the pre‐oxidation compound, c‐ 1 (538 nm).…”

Light‐Induced Dyotropic Rearrangement of Diarylethenes: Scope, Mechanism, and Prospects

“…Weight of the parent DAE o isomer used in the photolysis experiment, concentration, weight of the isolated DDA, and yield. [b] The peaks of the selected carbons in 13 C NMR are shown in color.…”

“…Introduction of any non-symmetrical element into the initial diarylethenes (different heterocyclic moieties or their substituents, or non-symmetric substituents on the central double bond) reduces the symmetry of the corresponding DDAs to C 1 that is present here as two enantiomers. The change in the structure led to a non-equivalence of methyl groups and the corresponding quaternary carbons appearing at 45-60 ppm in 13 C NMR spectra, which serve as spectroscopic markers for DDA formation. For the DDA 2 a reported for the first time, these signals were recorded at 59.6 and 65.8 ppm (for other DDAs, see Table 1).…”

“…An unexpected color change (coloration or bleaching) of substances upon exposure to UV light during common thin layer chromatography (TLC) or upon accidental exposure to sunlight, poor photochromic performance of novel compounds or its absence could give a hint to an unknown photoreaction. For instance, the following transformations have recently been discovered due to such observations: lightinduced reversible intramolecular [2 + 2] cycloaddition in 1H-2-benzo[c]oxocins [11] and cycloreversion of trioxobicyclononadiene derivatives, [12] oxidative base-induced dimerization of a thienyl-based ketoester to a 4-hydroxy-4-methylcyclopent-2ene-1-one derivative, [13] and photochemical rearrangement of oxazole-based diarylethenes to naphthalenes. [14] In this review, we will describe the state-of-the-art for an unusual photochemical reaction discovered during studies of diarylethene (DAE) photochromes with heterocyclic moieties.…”

The Endeavor of Diarylethenes: New Structures, High Performance, and Bright Future

“…Other works toward bridge structure–activity relationship and functional ethene bridges were also noteworthy. Hecht and co‐workers and Shirinian and co‐workers, respectively, studied the space conformation of the diarylcyclopentenes with substituted bridges and the size effect of the ethene bridge. Ahn and co‐workers discovered a dihydro‐4H‐thieno[2,3‐b]thiopyran‐4‐one ethene bridged diarylethene, whose closed isomer was highly emissive.…”