Recent Developments and Aspects of Industrial Fluoroalkylation

Fluoroalkylations have received increasing attention in the academic and industrial environment due to the particular properties of the active ingredients that are strongly influenced by fluoroalkyl substituents. The inherent difficulties of introducing a fluoroalkyl substituent into advanced intermediates has triggered the development of an enormous number of specialized reagents, which, however, are often not suitable for large scale applications. In contrast to this reagent based fluoroalkylation approach, the direct activation of industrially readily available fluoroalkyl halides could be more suitable for a large-scale process. In this way the dithionite initiated fluoroalkylation as well as newly developed catalytically activated fluoroalkylation protocols were considered for industrial large-scale applications.

Effect of Fluoroalkyl-Substituent in Bistolane-Based Photoluminescent Liquid Crystals on Their Physical Behavior

Photoluminescent liquid crystals (PLLCs) have attracted significant attention owing to their broad applicability in thermosensing and PL switching. Extensive efforts have been made to develop bistolane-based PLLCs containing flexible units at both molecular terminals, and it has been revealed that their PL behavior can switch with the phase transition between the crystalline and LC phases. Although slight modulation of the flexible unit structure dramatically alters the LC and PL behaviors, few studies into the modification of the flexible units have been conducted. With the aim of achieving dynamic changes in their physical behaviors, we developed a family of bistolane derivatives containing a simple alkyl or a fluoroalkyl flexible chain and carried out a detailed systematic evaluation of their physical behaviors. Bistolanes containing a simple alkyl chain showed a nematic LC phase, whereas switching the flexible chain in the bistolane to a fluoroalkyl moiety significantly altered the LC phase to generate a smectic phase. The fluoroalkyl-containing bistolanes displayed a stronger deep blue PL than their corresponding non-fluorinated counterparts, even in the crystalline phase, which was attributed to the construction of rigid molecular aggregates through intermolecular F···H and F···F interactions to suppress non-radiative deactivation.

Novel Fluorinated Porphyrins Sensitize Tumor Cells to Photodamage in Normoxia and Hypoxia: Synthesis and Biocompatible Formulations

Background: Hypoxia renders tumor cells refractory to treatment. One way to overcome this problem is the design of drug delivery systems that contain the antitumor agent within an oxygen supply medium. Objective: to evaluate whether the perfluorocarbon liquids (capable of retaining up to 50% v/v amounts of O2 gas) can be tools for delivery of photosensitizers to hypoxic tumors. Method: We synthesized a series of compounds in which fluoroaliphatic or fluoroaromatic moieties were conjugated to the porphyrin ring in meso-positions. Two derivatives were tested as the solutions prepared either from a dimethylformamide stock (‘free’ formulation) or from a perfluorocarbon emulsion in which the photosensitizer is entrapped in the oxygenated medium. Results: In the emulsion the hydrophobic photosensitizer and the gas transporting liquid represented a biocompatible composition. Free formulations or perfluorocarbon emulsions of fluorinated porphyrins evoked little-to-null dark cytotoxicity. In contrast, each formulation triggered cell death upon light activation. Photodamage in the presence of fluorinated porphyrins was achievable not only at normoxic (20.9% O2 v/v) conditions but also in hypoxia (0.5% O2). With new compounds dissolved in the medium the cell photodamage in hypoxia was negligible whereas a significant photodamage was achieved with the emulsions of fluorinated porphyrins. The derivative with the fluoroalkyl substituent was more potent than its structurally close analog carrying the fluoroaryl moiety. Conclusion: Our new fluorinated porphyrin derivatives, especially their emulsions in which the photosensitizer and the oxygenated medium are coupled into one phase, can be perspective for photoelimination of hypoxic tumor cells.