Il Yoon

Synthesis of novel long wavelength cationic chlorins via stereoselective aldol-like condensation

Using stereoselective aldol-like condensation as a key methodology, a series of chlorophyll a-based long wavelength cationic chlorins were synthesized using methyl pyropheophorbide a (MPPa) and purpurin-18-N-methoxylimide methyl ester as starting materials. Such long wavelength cationic chlorins possess covalently linked cationic moieties (pyridinium or quinolinium) on the peripheral of their tetrapyrrole macrocycles. It was found that all long wavelength cationic chlorins showed their longest absorption maxima in the range of 712-763nm, making them potential photosensitizers in photodynamic therapy. The results of preliminary experiments probing in vitro photodynamic effects showed that the purpurinimide derivatives exhibit relatively high phototoxicity in HeLa cells as compared to MPPa derivatives.

Gold Nanorod–Photosensitizer Complex Obtained by Layer-by-Layer Method for Photodynamic/Photothermal Therapy In Vitro

Gold nanorod (GNR)-photosensitizer (PS) complex was prepared using anionic PS (sodium salt of purpurin-18) and cationic poly(allylamine hydrochloride) by layer-by-layer method, and was characterized by transmission electron microscopy, UV-vis spectroscopy, and zeta potential. The GNR-PS complex is a promising agent for synergistic (photothermal and photodynamic) therapy (PTT/PDT), in which PTT generates heat as well as operates the PS release which maximize the following PDT activity. The combined dual therapy, PTT followed by PDT, exhibits a significantly higher photocytotoxicity result based on synergistic effect of hyperthermia from PTT as well as singlet oxygen photogeneration from PDT.

Synthesis, optical properties and preliminary in vitro photodynamic effect of pyridyl and quinoxalyl substituted chlorins.

A series of chlorophyll a-based chlorins conjugated with pyridyl or quinoxalyl group at different positions were synthesized, characterized and evaluated for their photodynamic effect in vitro. It was found that all the pyridyl and quinoxalyl chlorins showed promising photocytotoxicities but nontoxic without irradiation in HeLa cells, and the substituted types and positions had a significant influence on the photocytotoxicities of the chlorophyll a-based chlorins. All the chlorins with a pyridyl group at the C-D ring end exhibited relatively high photocytotoxicity as compared to those with 3(2)-pyridyl. Among them, compound 12 conjugated with a pyridyl group at its C12 position showed the best photodynamic effect in HeLa cells with an IC50 value of 0.033μM. These facts, associated with the relative high long wavelength absorptions of those chlorins may provide valuable ways to design and prepare promising photosensitizers for application in photodynamic therapy.

Sensor molecules for silver(i)-selective membranes based on mono-to quadri-dentate podands

A series of podands containing nitrogen and sulfur atoms are utilized as sensing components to prepare Ag + -selective polymeric membrane electrodes whose characteristics are dependent on the structure of each podand used.

Crystal structure of catena-poly[[(N,N-diethyl-3-mesitylsulfonyl-1H-1,2,4-triazole-1-carboxamide-κN1)silver(I)]-μ-nitrato-κ3O,O′:O]

The asymmetric unit of the title compound comprises one cafenstrole ligand molecule and one silver nitrate ion. The coordination bonds between silver and oxygen atoms allow a continuous one-dimensional coordination polymer structure along [001]. The three-dimensional architecture is stabilized by C—H⋯O hydrogen bonds and C—H⋯π interactions

Pu-18-N-butylimide-NMGA-GNP conjugate is effective against hepatocellular carcinoma

Background Photodynamic therapy (PDT) is a new modality in the treatment of cancer. This study thus aims to examine whether the PDT is effective against in vivo hepatocellular carcinoma. Methods In vivo efficacy of PDT on hepatocellular carcinoma was tested in xenografted mice with human hepatocellular carcinoma cell lines (Huh7) by utilizing a gold nanoparticles (GNPs) conjugate of new photosensitizer (PS), purpurin-18-N-butylimide-N-methyl-D-glucamine (Pu-18-N-butylimide-NMGA). The conjugate (PS-GNPs) was synthesized from the reaction between Pu-18-N-butylimide-NMGA and chloroauric acid (HAuCl4). Mice were arbitrarily assigned into one of three groups. First group received saline alone, second group received PS-GNPs alone, and the last group received both PS-GNPs and irradiation. PS-GNPs was injected directly into the tumor mass and irradiations were performed 24 hours after injection of PS-GNPs. Results Tumor volume was significantly smaller in the group which received both PS-GNPs and irradiation compared with other two groups. Western blot and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay revealed that the group which received both PS-GNPs and irradiation showed larger amount of apoptotic protein and DNA fragmentation compared with other two groups. Conclusion This study suggests that Pu-18-N-butylimide-NMGA-GNP conjugate is an effective agent for PDT in the treatment of hepatocellular carcinoma.

2,9,12,15,18,25,27,34,37,40,43,50-Dodeca­oxa-56-aza­hepta­cyclo­[24.24.5.151,55.03,8.019,24.028,33.044,49]hexa­penta­conta-3,5,7,19(24),20,22,28(33),29,31,44,46,48,51,53,55-penta­deca­ene

The title compound, C43H45NO12, was prepared from the reaction of 2,6-bis(dibromomethyl)pyridine and bisphenol in the presence of caesium carbonate as a base. The central ring makes dihedral angles of 64.83 (6), 13.48 (6), 56.96 (6) and 66.21 (6)° with the peripheral rings. In the crystal, molecules are linked by weak C—H⋯O and C—H⋯π interactions, forming a folded structure.