Photochemically Induced Intramolecular Radical Cyclization Reactions with Imines.

The photochemically induced intramolecular hydrogen abstraction or hydrogen atom transfer in cyclic imines 8a,b followed by a cyclization is investigated. Two types of products are observed, one resulting from the formation of a C-C bond, the other from the formation of a C-N bond. A computational study reveals that hydrogen is exclusively transferred to the imine nitrogen leading to a triplet diradical intermediate. After intersystem crossing, the resulting zwitterionic intermediate undergoes cyclization leading to the final product.

Gold-phosphine-porphyrin as potential metal-based theranostics.

Two new gold-phosphine-porphyrin derivatives were synthesized and fully characterized, and their photophysical properties investigated along a water-soluble analog. The cytotoxicity of the compounds was tested on cancer cells (HCT116 and SW480), and their cell uptake was followed by fluorescence microscopy in vitro (on SW480). The proof that the water-soluble gold-phosphine-porphyrin is a biologically active compound that can be tracked in vitro was clearly established, especially concerning the water-soluble analog. Some preliminary photodynamic therapy (PDT) experiments were also performed. They highlight a dramatic increase of the cytotoxicity when the cells were illuminated for 30 min with white light.

Synthesis and Characterization of Carbazole-Linked Porphyrin Tweezers.

Herein the synthesis, spectroscopic characterization, two-photon absorption and electrochemical properties of 3,6-disubstituted carbazole tweezers is reported. A dimer resulting from a Glaser homocoupling was isolated during a Sonogashira coupling reaction between a diethynyl-carbazole spacer and a 5-bromo-triarylporphyrin and the properties of this original compound were compared with the 3,6-disubstituted carbazole bisporphyrin tweezers. The dyads reported herein present a two-photon absorption maximum at 920 nm with two-photon absorption cross-section in the 1200 GM range. Despite a strong linear absorption in the Soret region and moderate fluorescence quantum yield, they both lead to a high brightness reaching 30 000 M(-1) cm(-1) .

Easy access to heterobimetallic complexes for medical imaging applications via microwave-enhanced cycloaddition.

The Cu(I)-catalysed Huisgen cycloaddition, known as "click" reaction, has been applied to the synthesis of a range of triazole-linked porphyrin/corrole to DOTA/NOTA derivatives. Microwave irradiation significantly accelerates the reaction. The synthesis of heterobimetallic complexes was easily achieved in up to 60% isolated yield. Heterobimetallic complexes were easily prepared as potential MRI/PET (SPECT) bimodal contrast agents incorporating one metal (Mn, Gd) for the enhancement of contrast for MRI applications and one "cold" metal (Cu, Ga, In) for future radionuclear imaging applications. Preliminary relaxivity measurements showed that the reported complexes are promising contrast agents (CA) in MRI.

Design, synthesis and biological evaluation of conformationnally-restricted analogues of E7010 as inhibitors of tubulin assembly (ITA) and vascular disrupting agents (VDA).

Vascular-disrupting agents (VDA) specifically target established neovasculature which results in vascular shutdown. This therapeutic strategy could improve the outcome of pathologies involving aberrant angiogenesis. Although several classes of VDA exist, inhibitors of tubulin assembly (ITA) represent the main category. A series of 21 conformationnally-restricted analogues of E7010, a known ITA-VDA, were designed and synthesised as novel inhibitors of tubulin assembly (ITA) and vascular-disrupting agents (VDA). Among them, indole 4j exhibited good potency against HUVEC and HIG-82 cell lines, as well as a good ability to inhibit tubulin assembly. Furthermore, indole 4j reduced HUVEC migration in a dose-dependent manner, indicating a vascular disrupting activity comparable to that of the gold standard, Combretastatin A4 (CA4).

Synthesis and luminescent properties of cis bis-N-heterocyclic carbene platinum(II) bis-arylacetylide complexes.

A series of luminescent N-heterocyclic carbene platinum(II) complexes, [(pmim)Pt(C≡C-R)(2)] (R = C(6)H(5) (2), C(6)H(4)OMe (3), C(6)H(2)(OMe)(3) (4), C(6)H(4)NMe(2) (5), C(4)H(3)S (6), C(6)H(4)C≡CC(6)H(5) (7), 1-pyrenyl (8), and C(6)H(4)F (9)), were successfully synthesized using the precursor (pmim)PtI(2), 1 (pmim = 1,1'-dipentyl-3,3'-methylene-diimidazoline-2,2'-diylidene). The X-ray crystal structures of 1, 4, 5, and 7 have been determined. These complexes showed long-lived emission in solution at room temperature. The emission origin of the complexes is tentatively assigned to be from triplet states of predominantly intraligand (IL) character with some mixing of metal-to-ligand charge-transfer (MLCT) character. TD-DFT and DFT calculations have been performed on most of the complexes to ascertain the nature of the excited state. Changes in the alkynyl ligands lead to a change in the absorption and emission maxima seen for these complexes in a potentially predictable way.

Synthesis and Antiviral Activity Evaluation of Nitroporphyrins and Nitrocorroles as Potential Agents against Human Cytomegalovirus Infection.

Different nitroporphyrinoid derivatives were synthesized and studied as potential agents against human Cytomegalovirus. Interestingly, two nitrocorroles display strong activity against human Cytomegalovirus with IC 50 < 0.5 µM. These compounds also possess antiproliferative activities without detected in vivo toxicity. Therefore, nitrocorroles appear for the first time as potential active compounds that can be applied in human health.