@article{WessigFreyseSchusteretal.2020, author = {Wessig, Pablo and Freyse, Daniel and Schuster, David and Kelling, Alexandra}, title = {Fluorescent dyes with large stokes shifts based on Benzo[1,2-d:4,5-d']bis([1,3]dithiole) ("S4-DBD Dyes")}, series = {Europan journal of organic chemistry}, volume = {2020}, journal = {Europan journal of organic chemistry}, number = {11}, publisher = {Wiley}, address = {Weinheim}, issn = {1434-193X}, doi = {10.1002/ejoc.202000093}, pages = {1732 -- 1744}, year = {2020}, abstract = {We report on a further development of [1,3]-dioxolo[4.5-f]benzodioxole (DBD) fluorescent dyes by replacement of the four oxygen atoms of the heterocyclic core by sulfur atoms. This variation causes striking changes of the photophysical properties. Whereas absorption and emission significantly shifted to longer wavelength, the fluorescence lifetimes and quantum yields are diminished compared to DBD dyes. The latter effect is presumably caused by an enhanced intersystem crossing to the triplet state due to the sulfur atoms. The very large Stokes shifts of the S-4-DBD dyes ranging from 3000 cm(-1) to 7400 cm(-1) (67 nm to 191 nm) should be especially emphasized. By analogy with DBD dyes a broad variation of absorption and emission wavelength is possible by introducing different electron withdrawing substituents. Moreover, some derivatives for coupling with biomolecules were developed.}, language = {en} } @article{WessigJohnSperlichetal.2020, author = {Wessig, Pablo and John, Leonard and Sperlich, Eric and Kelling, Alexandra}, title = {Sulfur tuning of [1,3]-dioxolo[4.5-f]benzodioxole (DBD) fluorescent dyes}, series = {European journal of organic chemistry}, volume = {2021}, journal = {European journal of organic chemistry}, number = {3}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1434-193X}, doi = {10.1002/ejoc.202001418}, pages = {499 -- 511}, year = {2020}, abstract = {The replacement of oxygen by sulfur atoms of [1,3]-dioxolo[4.5-f]benzodioxole (DBD) fluorescent dyes is an efficient way to adjust the photophysical properties (sulfur tuning). While previously developed S-4-DBD dyes exhibit considerably red-shifted absorption and emission wavelength, the heavy atom effect of four sulfur atoms cause low fluorescence quantum yields and short fluorescence lifetimes. Herein, we demonstrate that the replacement of less than four sulfur atoms (S-1-DBD, 1,2-S-2-DBD, and 1,4-S-2-DBD dyes) permits a fine-tuning of the photophysical properties. In some cases, a similar influence on the wavelength without the detrimental effect on the quantum yields and lifetimes is observed. Furthermore, the synthetic accessibility of S-1- and S-2-DBD dyes is improved, compared with S-4-DBD dyes. For coupling with biomolecules a series of reactive derivatives of the new dyes were developed (azides, OSu esters, alkynes, maleimides).}, language = {en} } @article{BuechnerJohnMertensetal.2018, author = {B{\"u}chner, D{\"o}rthe and John, Leonard and Mertens, Monique and Wessig, Pablo}, title = {Detection of dsDNA with [1,3]Dioxolo[4,5-f]benzodioxol (DBD) Dyes}, series = {Chemistry - a European journal}, volume = {24}, journal = {Chemistry - a European journal}, number = {60}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {0947-6539}, doi = {10.1002/chem.201804057}, pages = {16183 -- 16190}, year = {2018}, abstract = {DBD fluorescent dyes have proven to be useful in numerous applications. To widen the range of biological applications, we propose three different types of DBD molecules that have been modified in such a way that DNA interaction becomes probable. After the successful synthesis of all three compounds, we tested their fluorescent properties and their DNA binding abilities. Two of the three probes exhibit an interaction with dsDNA with subsequent fluorescence enhancement. The determined binding constants of the two new DNA dyes are comparable to other minorgroove-binding dyes. Their large Stokes shifts and their long fluorescent lifetimes are outstanding features of these dyes.}, language = {en} } @article{SchultzeSchmidt2018, author = {Schultze, Christiane and Schmidt, Bernd}, title = {Ring-closing-metathesis-based synthesis of annellated coumarins from 8-allylcoumarins}, series = {Beilstein journal of organic chemistry}, volume = {14}, journal = {Beilstein journal of organic chemistry}, publisher = {Beilstein-Institut zur F{\"o}rderung der Chemischen Wissenschaften}, address = {Frankfurt, Main}, issn = {1860-5397}, doi = {10.3762/bjoc.14.278}, pages = {2991 -- 2998}, year = {2018}, abstract = {8-Allylcoumarins are conveniently accessible through a microwave-promoted tandem Claisen rearrangement/Wittig olefination/cyclization sequence. They serve as a versatile platform for the annellation of five- to seven-membered rings using ring-closing olefin metathesis (RCM). Furano-, pyrano-, oxepino- and azepinocoumarins were synthesized from the same set of precursors using Ru-catalyzed double bond isomerizations and RCM in a defined order. One class of products, pyrano[2,3-f]chromene-2,8-diones, were inaccessible through direct RCM of an acrylate, but became available from the analogous allyl ether via an assisted tandem catalytic RCM/allylic oxidation sequence.}, language = {en} } @article{SchmidtHaukeMuehlenberg2014, author = {Schmidt, Bernd and Hauke, Sylvia and Muehlenberg, Nino}, title = {Imino glycals via Ruthenium-catalyzed RCM and isomerization}, series = {Synthesis}, volume = {46}, journal = {Synthesis}, number = {12}, publisher = {Thieme}, address = {Stuttgart}, issn = {0039-7881}, doi = {10.1055/s-0033-1338615}, pages = {1648 -- 1658}, year = {2014}, abstract = {N-Allyl-N-homoallylamines were converted in one step into cyclic enamides via a ruthenium-catalyzed assisted tandem catalytic ring-closing metathesis-isomerization sequence. The sequence relies on the in situ transformation of a metathesis active Ru-carbene into an isomerization active Ru-hydride by addition of hydroxide as a chemical trigger.}, language = {en} }