685893-20-3Relevant academic research and scientific papers
4-Cyano-6,7-dimethoxycarbostyrils with solvent- and pH-independent high fluorescence quantum yields and emission maxima
Ahvale, Appasaheb B.,Prokopcova, Hana,Sefcovicova, Jana,Steinschifter, Waltraud,Taeubl, Anna E.,Uray, Georg,Stadlbauer, Wolfgang
, p. 563 - 571 (2008/09/18)
Highly fluorescent and stable 6,7-dimethoxy-2-oxoquinoline-4-carbonitriles (11) were synthesized starting from appropriate 4-hydroxyquinolones 3 via reactive 4-chloroquinolones 8 by using toluenesulfinates as catalysts. In contrast to the well-described 4-trifluoromethyl-substituted analogues 18, N-substituted derivatives 11 fluoresce in water, polar, and apolar solvents in a narrow 430-440-nm window with almost constant quantum yield of 0.5. Equal excitation is possible in the broad double maximum between 385 and 410 nm yielding identical data between pH 1 and 11. These properties could lead to a broadly usable fluorescence standard. N-Alkylation with bromoacetate yields ester 13 in good yields. Reactive succinimidoyl (OSu) ester 15 was prepared by saponification to acid 14. With amino acids or peptides, linking to labeled derivatives 17 was achieved under mild conditions in slightly basic aqueous media. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
