A Fluorinated Carbanionic Substituent for Improving Water Solubility and Lipophilicity of Fluorescent Dyes

Abstract

Installation of a carbanionic substituent, that is strongly stabilized by two (trifluoromethyl)sulfonyl (Tf = SO 2 CF 3) groups, into several fluorescence dyes including boron-dipyrromethenes (BODIPYs), fluoresceins, and aminocoumarins has been achieved by the 2,2-bis(triflyl)ethylation reaction of the dye frameworks with highly electrophilic Tf 2 C = CH 2 , followed by neutralization with NaHCO 3. Despite the contradiction between water solubility and lipophilicity, the carbanion-decorated dyes thus obtained showed significant enhancement of not only water solubility but also lipophilicity. This work clearly demonstrates that the fluorinated, highly stabilized carbanionic substituent is a new option for controlling the macroscopic property of chemical materials. Water solubility (and aqueous solubility) is a key macroscopic property for chemical materials directed towards biorelevant applications. [1] The most common way to improve the water solubility of less soluble compounds is introduction of ionic groups such as the sulfonato group into the molecular structure (Figure 1 A). However, such ionic functionalities

GlycoBODIPYs: Sugars Serving as a Natural Stock for Water‐soluble Fluorescent Probes of Complex Chiral Morphology

“…[15] Certain hydroxy functions or even complete sugar units can be redundant or derivatized, [16] as was also recently found in our group. [17] Although BODIPYs have already been transformed into water-soluble analogues by various approaches (Scheme 1) such as by sulfonation, [18] introduction of ammonium, [19] carboxylate, [20] multiple PEG residues, [21] or recently by a bistriflyl-substituted carbanion, [22] most of them suffer from a tedious synthetic route (sulfonated peptidyl linkers), [19] the incorporation of unnecessary structural ballast (PEG), or from the introduced charge, which can impair facile cell-uptake and further functionalizations in organic media. Furthermore, the native fluorescence of BODIPYs can often be substantially compromised after the derivatization process (PEG, peptidyl linkers, meso pyridinium [23] ).…”

Metal-Free C–C/C–N/C–C Bond Formation Cascade for the Synthesis of (Trifluoromethyl)sulfonylated Cyclopenta[b]indolines

“…In addition, taking advantage of the chameleonic reactivity of sulfonyl compounds, the gem -bis(triflyl)ated indoline products were successfully derivatized into the highly functionalized indolines with fluorinated substituents, which may yield interesting properties. 10 , 11 …”