Synthesis of boronated meso-arylporphyrins via copper-catalyzed 1,3-dipolar cycloaddition reaction and their binding ability towards albumin and low density lipoproteins

Synthesis of new representatives of A3B-type carboranylporphyrins based on meso-tetra(pentafluorophenyl)porphyrin transformations

A carboranylporphyrin of A3B-type bearing a single pentafluorophenyl ring was prepared through the regioselective nucleophilic aromatic substitution reaction of the p-fluorine atoms in 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin with 9-mercapto-m-carborane. The reaction of this porphyrin with sodium azide led to the selective substitution of the p-fluorine atom in the pentafluorophenyl substituent with an azide functionality which upon reduction with SnCl2 resulted in the formation of the corresponding porphyrin with an amino group. Pentafluorophenyl-substituted A3B-porphyrins were studied and transformed to thiol and amino-substituted compounds allowing for the preparation of porphyrins with different reactive groups such as hydroxy and amino derivatives capable for further functionalization and conjugation of these porphyrins to other substrates. In addition, conjugates containing maleimide or biotin entities in the structure of carborane A3B-porphyrin were also synthesized based on the amino-substituted A3B-porphyrin. The structures of the prepared carboranylporphyrins were determined by UV-vis, IR, 1H, 19F, 11B NMR spectroscopic data and MALDI mass spectrometry.

CuAAC-inspired synthesis of 1,2,3-triazole-bridged porphyrin conjugates: an overview

Among all the available approaches in organic synthesis, the "click chemistry" protocol is very common nowadays to covalently connect two diverse moieties in a single framework. Therefore, this review focuses on the synthesis and photophysical studies of β- and meso-substituted and 1,2,3-triazole-fused porphyrin conjugates. All of the porphyrin conjugates discussed here are synthesized via a copper(I)-catalyzed Huisgen 1,3-dipolar cycloaddition reaction between an azide and a terminal alkyne, also popular as "click reaction" or CuAAC reaction. Moreover, the 1,2,3-triazole ring also serves as a spacer and an electron transfer bridge between the porphyrin and the attached chromophores. In order to provide a critical overview of the synthesis and properties of various porphyrin-triazole hybrids, this review will discuss some of the key reactions involved in the preparation of triazole-linked porphyrin conjugates.

Multicomponent Molecular Systems Based on Porphyrins, 1,3,5-Triazine and Carboranes: Synthesis and Characterization

2,4,6-Trichloro-1,3,5-triazine (cyanuric chloride) is an excellent coupling reagent for the preparation of highly structured multifunctional molecules. Three component systems based on porphyrin, cyanuric chloride and carborane clusters were prepared by a one-pot stepwise amination of cyanuric chloride with 5-(4-aminophenyl)-10,15,20-triphenylporphyrin, followed by replacement of the remaining chlorine atoms with carborane S- or N-nucleophiles. Some variants of 1,3,5-triazine derivatives containing porphyrin, carborane and residues of biologically active compounds such as maleimide, glycine methyl ester as well as thioglycolic acid, mercaptoethanol and hexafluoroisopropanol were also prepared. A careful control of the reaction temperature during the substitution reactions will allow the synthesis of desired compounds in a good to high yields. The structures of synthesized compounds were determined with UV-vis, IR, ¹H NMR, ¹¹B NMR, MALDI-TOF or LC-MS spectroscopic data. The dark and photocytotoxicity as well as intracellular localization and photoinduced cell death for compounds 8, 9, 17, 18 and 24 were evaluated.

Investigations on the Synthesis, Reactivity, and Properties of Perfluoro-α-Benzo-Fused BOPHY Fluorophores

The synthesis and reactivity of 3,8-dibromo-dodecafluoro-benzo-fused BOPHY 2 are reported, via S_N Ar with O-, N- S- and C-nucleophiles, and in Pd(0)-catalyzed cross-coupling reactions (Suzuki and Stille). The resulting perfluoro-BOPHY derivatives were investigated for their reactivity in the presence of various nucleophiles. BOPHY 3 displays reversible color change and fluorescence quenching in the presence of bases (Et₃ N, DBU), whereas BOPHY 7 reacts preferentially at the α-pyrrolic positions, and BOPHY 8 undergoes regioselective fluorine substitution in the presence of thiols. The structural and electronic features of the fluorinated BOPHYs were studied by TD-DFT computations. In addition, their spectroscopic and cellular properties were investigated; BOPHY 10 shows the most red-shifted absorption/emission (λ_max 659/699 nm) and 7 the highest fluorescence (Φ_f =0.95), while all compounds studied showed low cytotoxicity toward human HEp2 cells and were efficiently internalized.