859322-94-4Relevant academic research and scientific papers
A new approach to silicon rhodamines by Suzuki–Miyaura coupling – scope and limitations
Kanagasundaram, Thines,Timmermann, Antje,Kramer, Carsten S.,Kopka, Klaus
, p. 2569 - 2576 (2019)
Background: Silicon rhodamines are of particular interest because of their advantageous dye properties (fluorescence- and biostability, quantum efficiency, tolerance to photobleaching). Therefore, silicon rhodamines find frequent application in STED (stimulated emission depletion) microscopy, as sensor molecules for, e.g., ions and as fluorophores for the optical imaging of tumors. Different strategies were already employed for their synthesis. Because of just three known literature examples in which Suzuki–Miyaura cross couplings gave access to silicon rhodamines in poor to moderate yields, we wanted to improve these first valuable experimental results. Results: The preparation of the xanthene triflate was enhanced and several boron sources were screened to find the optimal coupling partner. After optimization of the palladium catalyst, different substituted boroxines were assessed to explore the scope of the Pd-catalyzed cross-coupling reaction. Conclusions: A number of silicon rhodamines were synthesized under the optimized conditions in up to 91% yield without the necessity of HPLC purification. Moreover, silicon rhodamines functionalized with free acid moieties are directly accessible in contrast to previously described methods.
Novel rhodamine dyes via suzuki coupling of xanthone triflates with arylboroxins
Calitree, Brandon D.,Detty, Michael R.
scheme or table, p. 89 - 92 (2010/07/16)
Novel rhodamine dyes were prepared from xanthone precursors in a 'one-pot' procedure via reaction of the xanthone with trifluoromethanesulfonic anhydride followed by Pd-mediated Suzuki coupling between the xanthone triflate and an arylboroxin. Rhodamines with 9-(3- or 4-carboxyphenyl) and 9-(3-nitrophenyl) substituents were prepared by this procedure. The procedure also works well with thio- and selenoxanthones, but not with telluroxanthones. Georg Thieme verlag Stuttgart.
