- Selective synthesis of C32- and C20-monoiodinated chlorophyll derivatives
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A chlorophyll derivative possessing an iodine atom at the C3-moiety was synthesized from methyl pyropheophorbide-a for the first time using phenyliodine bis(trifluoroacetate) and I2. The use of larger amounts of reagents resulted in additional iodination at the C20-position, thus affording the 3,20-diiodo derivative. The iodine atom at the C3-moiety of the 3,20-diiodo derivative could be removed selectively by treating with NaN3, thus affording the 3-vinyl-20-iodo derivative.
- Oba, Toru,Miyata, Kota,Masuya, Takuto,Yasuda, Satoru,Ito, Satoshi
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- Protonation-deprotonation equilibria in tetrapyrroles Part 2:
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The two-dimensional 1H, 13C and 1H, 15N heteronuclear single quantum coherence (HSQC) and heteronuclear multiple bond correlation (HMBC) NMR techniques were applied to investigate the formation of N-protonated c
- Hynninen, Paavo H.,Mesilaakso, Markku
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- Chlorophylls. IX. the first phytochlorin-fullerene dyads: Synthesis and conformational studies
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The first chlorin-fullerene electron donor-acceptor (DA) compounds have been synthesized. The synthesis produced C-2′ R and Sepimers, both of which exhibited atropisomerism regarding the mutual orientation of the fullerene ball and the propionic acid residue of the phytochlorin unit. The atropisomerism arises from the short linkage between the Ceo ball and the chlorin ring, which hinders free rotation of the bulky ball. Dynamic H NMR and molecular modelling were used in concert to investigate the atropisomerism in the metal-free DA molecules 5. The dynamic NMR-measurements showed a lower energy barrier [Ea = 21.4(5) kcal mol 1] for one stereoisomer and a higher one [£a = 23.0(8) kcal mol1] for the three other stereoisomers. MM+ molecular mechanic calculations were performed for each C-2 epimer to assess the potential energy as a function of the angle of rotation about the C3-C2 single bond. For the C-2 R and Sepimers, these calculations produced two potential energy curves that showed a near mirror-image relationship. Solvation phenomena were proposed to play an essential role in the stabilization of the isomers. Fast intramolecular photoinduced electron transfer from the chlorin donor to the fullerene acceptor was observed in polar solvents. Copyright 1999 by the Royal Society of Chemistry.
- Helaja, Juho,Tauber, Andrei Y.,Abel, Yvonne,Tkachcnko, Nikolai V.,Lemmetyinen, Helge,Kilpelaeinen, Ilkka,Hynnincn, Paavo H.
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- Nickel complexes of chlorophyll derivatives
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Nickel complexes of certain phorbine and amide derivatives of chlorophyll a were synthesized. Most of the chlorophyll a derivatives studied form nickel complexes when boiled in toluene with an equimolar amount of nickel acetylacetonate in high yield. The yields of the nickel complexes of the chlorophyll derivatives are determined by the stability of the starting ligand under the reaction conditions.
- Belykh,Tarabukina,Matveev,Kuchin
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- Isolation of pyropheophorbide a from the leaves of Atalantia monophylla (Roxb.) Corr. (Rutaceae) as a possible antiviral active principle against herpes simplex virus type 2
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Antiviral activity-guided isolation studies on the leaves of Atalantia monophylla (ROXB.) CORR. (Rutaceae) led to the identification of pyropheophorbide a (1), a simple chlorin derivative, from the chloroform extract (fr. B) as a possible antiviral active principle against herpes simplex virus type 2 (HSV-2). Pyropheophorbide a methyl ester (2) was also isolated from the hexane extract (fr. A).
- Chansakaow, Sunee,Ruangrungsi, Nijsiri,Ishikawa, Tsutomu
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- Photosensitizers derived from 132-oxo-methyl pyropheophorbide-a: Enhanced effect of indium(III) as a central metal in in vitro and in vivo photosensitizing efficacy
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The effects of an additional keto group on absorption wavelength and the corresponding metal complexes Zn(II), Cu(II) In(III) on singlet oxygen production and photodynamic efficacy were examined among the alkyl ether analogs of pyropheophorbide-a. For the preparation of the desired photosensitizers, the methyl 132-oxo-pyropheophorbide-a obtained by reacting methyl pyropheophorbide-a with aqueous LiOH-THF was converted into a series of alkyl ether analogs. These compounds were evaluated for photophysical properties and in vitro (by means of the MTT assay and intracellular localization in RIF cells) and in vivo (in C3H mice implanted with RIF tumors) photosensitizing efficacy. Among the alkyl ether derivatives, the methyl 3-decyloxyethyl-3-devinyl-13 2-oxo-pyropheophorbide-a was found to be most effective and the insertion of In(III) into this analog further enhanced its in vitro and in vivo photosensitizing efficacy. Fluorescence microscopy showed that, in contrast to the hexyl and dodecyl ether derivatives of HPPH (which localize in mitochondria and lysosomes, respectively), the diketo-analogs and their In(III) complexes localized in Golgi bodies. The preliminary in vitro and in vivo results suggest that, in both free-base and metalated analogs, the introduction of an additional keto group at the five-member exocyclic ring in pyropheophorbide-a diminishes its photosensitizing efficacy. This may be due to a shift in subcellular localization from mitochondria to the Golgi bodies. The further introduction of In(III) enhances photoactivity, but not by shifting the localization of the photosensitizer.
- Rosenfeld, Andrew,Morgan, Janet,Goswami, Lalit N.,Ohulchanskyy, Tymish,Zheng, Xiang,Prasad, Paras N.,Oseroff, Allan,Pandey, Ravindra K.
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- Demetalation kinetics of the zinc chlorophyll derivative possessing two formyl groups:
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Demetalation kinetics of zinc chlorophyll derivative 1 possessing two formyl groups directly linked to the A- and B-rings of the chlorin macrocycle, which was synthesized from chlorophyll b, was examined under acidic conditions and compared with those of
- Sadaoka, Kana,Oba, Toru,Tamiaki, Hitoshi,Kashimura, Shigenori,Saga, Yoshitaka
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- Transformation of carbonyl to vinylidene groups in the π-conjugated peripheral substituent of chlorophyll derivatives by Tebbe reagent
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The 131-oxo-moiety of chlorophyll-a derivatives including methyl (pyro)pheophorbides-a, mesopyropheophorbide-a, and bacteriopheophorbide-d possessing vinyl, ethyl, and 1-hydroxyethyl groups, respectively, at the 3-position was transformed into the corresponding exo-methylene group by treatment of Tebbe reagent. The synthetic procedures were useful for the regioselective conversion of the carbonyl to vinylidene group at the 3-position and naturally occurring chlorophyll-d (3-CHO) was successfully modified to chlorophyll-a (3-CH=CH2). Under the methylenation conditions, ester-carbonyl, hydroxy, and allyl groups in the peripheral substituents were tolerant as well as an acid-labile magnesium at the central position of chlorophylls.
- Tamiaki, Hitoshi,Tsuji, Kazuki,Machida, Shinnosuke,Teramura, Misato,Miyatake, Tomohiro
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- Comparison of demetalation properties between zinc chlorin and zinc porphyrin derivatives: Effect of macrocyclic structures
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Metalloporphyrins and metallochlorins are important biological molecules in nature. To examine the effect of macrocyclic structures on removal of central metals from these cyclic tetrapyrrole molecules without peripheral substitution effects, demetalation of zinc methyl pyropheophorbide a (zinc chlorin 1) and zinc methyl protopyropheophorbide a (zinc porphyrin 2) was kinetically analyzed under acidic conditions. Both 1 and 2 exhibited gradual spectral changes from zinc complexes to free-base forms with several isosbectic points in acetone/water (10:1) at the proton concentration of 6.1 × 10-3 M. Demetalation of zinc porphyrin 2 was slower than that of zinc chlorin 1 in the temperature range between 15 and 35 °C. This indicates that the porphyrin macrocycle provides tolerance to removal of the central metal from cyclic tetrapyrrole ligands compared with the chlorin macrocycle.
- Saga, Yoshitaka,Hojo, Sayaka,Hirai, Yuki
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- Artificial zinc chlorin dyes for dye sensitized solar cell
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Novel artificial zinc chlorin dyes comprising amine anchoring groups zinc aminochlorin (ZnChl-NH2), zinc monomethylaminochlorin (ZnChl-NHMe) and zinc dimethylaminochlorin (ZnChl-NMe2) are synthesized and their photovoltaic performances are evaluated in dye-sensitized solar cells. To the best of our knowledge, -NH2 functionalized Zn chlorin dyes are tested in dye-sensitized solar cells for the first time. Best efficiency is obtained with ZnChl-NHMe sensitizer with a 2.67 mA/cm2 short circuit photocurrent density, 414 mV of open circuit voltage, 0.64 of filling factor, and 0.68 of overall light to power conversion efficiency.
- Ocakoglu, Kasim,Erten-Ela, Sule,Saleem Joya,Harputlu, Ersan
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- Effects of the 13-keto group in the E-ring of zinc chlorophyll derivatives on demetalation kinetics under acidic conditions
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Zinc methyl 131-deoxopyropheophorbide a, which lacked the 13 1-oxo group in the exo five-membered E-ring, exhibited faster demetalation kinetics than zinc methyl pyropheophorbide a under acidic conditions, indicating that the 13-keto group of chlorophyllous pigments was responsible for resistance against removal of the central metal from the chlorin macrocycle.
- Saga, Yoshitaka,Maruko, Akane,Sadaoka, Kana,Takahashi, Naoya
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- Synthesis of a novel cyclic chlorophyll hetero-dyad as a model compound for stacked chlorophylls found in photosynthetic systems
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A covalently doubly linked cyclic chlorophyll hetero-dyad was stereospecifically prepared as a model for naturally stacked chlorophyll suprastructures. In the synthetic dyad, two composite macrocycles are situated very close to each other such that the Qy transition dipole moments intramolecularly interact to give intense circular dichroism peaks. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.
- Kosaka, Nobuo,Tamiaki, Hitoshi
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- The synthesis of chlorophyll-a skeleton homologs bearing linear six-carbon chain from methyl pheophorbide-a
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The synthesis of chlorins bearing 6C-straight chain was accomplished from methyl pheophorbide-a. A series of chemical modifications were employed for the construction of active functional groups, such as bromine atom or aldehyde group, on the periphery of chlorins. These functionalized chlorins further reacted with the reagent containing straight carbon-chain by common chemical reactions to produce target compounds. The structures of all new chlorins were characterized by elemental analysis, IR, UV-Vis and 1H NMR spectra.
- Wang,Han,Shim
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- Much enhanced catalytic reactivity of cobalt chlorin derivatives on two-electron reduction of dioxygen to produce hydrogen peroxide
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Effects of changes in the redox potential or configuration of cobalt chlorin derivatives (CoII(Chn) (n = 1-3)) on the catalytic mechanism and the activity of two-electron reduction of dioxygen (O2) were investigated based on the detailed kinetic study by spectroscopic and electrochemical measurements. Nonsubstituted cobalt chlorin complex (CoII(Ch1)) efficiently and selectively catalyzed two-electron reduction of dioxygen (O2) by a one-electron reductant (1,1′-dimethylferrocene) to produce hydrogen peroxide (H2O2) in the presence of perchloric acid (HClO4) in benzonitrile (PhCN) at 298 K. The detailed kinetic studies have revealed that the rate-determining step in the catalytic cycle is the proton-coupled electron transfer reduction of O2 with the protonated CoII(Ch1) complex ([CoII(Ch1H)]+), where one-electron reduction potential of [CoIII(Ch1)]+ was changed from 0.37 V (vs SCE) to 0.48 V by the addition of HClO4 due to the protonation of [CoIII(Ch1)]+. The introduction of electron-withdrawing aldehyde group (position C-3) (CoII(Ch3)) and both methoxycarbonyl group (position C-132) and aldehyde group (position C-3) (CoII(Ch2)) on the chlorin ligand resulted in the positive shifts of redox potential for Co(III/II) from 0.37 V to 0.45 and 0.40 V, respectively, whereas, in the presence of HClO4, no positive shifts of those redox potentials for [CoIII(Chn)]+/CoII(Chn) (n = 2, 3) were observed due to lower acceptability of protonation. As a result, such a change in redox property resulted in the enhancement of the catalytic reactivity, where the observed rate constant (kobs) value of CoII(Ch3) was 36-fold larger than that of CoII(Ch1).
- Mase, Kentaro,Ohkubo, Kei,Fukuzumi, Shunichi
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- Synthesis of methyl (132R/S)-alkyl-pyropheophorbide a and a non-epimerized chlorophyll a mimic
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The (132R/S)-methoxycarbonyl group of methyl pheophorbides a/a′ (chlorophyll a/a′ derivatives) was converted to methyl, ethyl, propyl, and isopropyl groups through the C132-alkylation under basic conditions followed by pyrolysis in 2,4,6-collidine with lithium iodide. All the resulting products, methyl 132-alkyl-pyropheophorbides a, predominantly gave the (132R)-stereoisomers with about one tenth of the (132S)-epimers. Their stereochemistry was determined by 1D/2D NMR and their optical properties were characterized by visible absorption and circular dichroism spectroscopy. Methyl (132R)-propyl-pyropheophorbide a was converted to (132R)-propyl-pyrochlorophyll a by ester exchanging and magnesium chelating reactions. The synthetic chlorophyll a analogue showed non-epimerization at the 132-position in pyridine-d5 at 40 °C, while naturally occurring chlorophyll a was easily epimerized under the same conditions to give its epimeric mixture.
- Ogasawara, Shin,Tamiaki, Hitoshi
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- Synthesis of 3-pyrazolinyl chlorins related to chlorophyll by 1,3-dipolar cycloaddition reaction from methyl pheophorbide-a
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The synthesis of a series of 3-pyrazolinyl-substituted chlorins, possessing different basic skeletons of chlorophyll degradation products such as pheophorbide-a, pyropheophorbide- a, purpurin-18, purpurin-7, purpurin-5, chlorin-p6, and chlorin-e6, was fulfilled from methyl pheophorbide-a by chemical modification and 1,3-dipolar cycloaddition with diazomethane. The structures of new chlorins were characterized by ultraviolet (UV), infrared (IR), 1H NMR, and mass spectra and elemental analysis. Taylor & Francis Group,LLC.
- Wang, Jin-Jun,Liu, Chun-Lin,Li, Jia-Zhu
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- Unexpected methylation and propylation of porphyrin E-ring during the hemisynthesis of deoxophylloerythroetioporphyrin (DPEP)
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An improved hemisynthesis of DPEP from chlorophyll a is described. Hydrogenation of the vinyl group avoided the cleavage to a 3-H porphyrin, while heating in triazabicyolodecene performed the decarboxylation of the side-chain and the aromatization of ring D. Under these conditions extensive methylation and propylation of ring E occurred in the presence of CH2X2 (X = Cl, Br).
- Jeandon, Christophe,Ocampo, Ruben,Callot, Henry J.
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- Novel chlorophyll a derivatives with ester-linked galactose fragments for photodynamic therapy and fluorescence diagnostics of cancer
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In the present work, a number of chlorophyll a derivatives were synthetized with galactose fragments with an ester bond between macrocycle and carbohydrate fragments. It showed that synthesized compounds fluoresce intensely inside HeLa cells, which enable these compounds to be considered as potential diagnostic agents and indicates their ability to remain in the cell in an unassociated photoactive state-A necessary condition for the realization of a photodynamic action. It was determined that while all conjugates had comparable photoinduced toxicities, the conjugate with phorbin macrocycle fragment had a much lower dark toxicity, which corresponds to the trends noted earlier. In terms of a therapeutic window, conjugate significantly exceeds similar derivatives of chlorin e6 and is the most promising for further research.
- Mal'Shakova, Marina V.,Velegzhaninov, Ilya O.,Rasova, Elena E.,Belykh, Dmitry V.
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p. 135 - 144
(2021/01/11)
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- Synthesis of 20-substituted chlorophyll derivatives with F-ring and optical properties of their less distorted chlorin π-systems
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Under acidic conditions, methyl bacteriopheophorbides-d bearing a variety of substituents at the 20-position were dehydrated in a 1-hydroxyethyl group at the 3-position to give methyl 20-substituted pyropheophorbides-a. In the same pot, the resulting 3-vinyl group was successively cyclized at the 5-position to afford the corresponding 3,5-ethano-chlorins as analogs of sedimentary porphyrins with two exo-five-membered rings. The 20-substitution is essential to the cyclization to produce the additionally fused F-ring. After the ring closure, the 20-bromine atom and acetyl group were removed by the action of the same acid to give the 20-unsubstituted product. The steric size of the 20-substituents affected the cyclization as well as the electronic absorption and emission of the 3,5-ethano-chlorins in a solution. The F-ring fusion suppressed the conformational distortion of the chlorin π-plane, partially regulating the optical properties: decrease of red shifts in Qy maxima by the 20-substitution and reduction of almost all Stokes shifts.
- Takarada, Yuki,Doi, Marie,Ogasawara, Shin,Tamiaki, Hitoshi
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supporting information
(2021/06/17)
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- Site-selective C20-fluorinations of chlorophyll-a derivatives using N-fluorobenzenesulfonimide and their optical properties
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Site-selective fluorinations at the C20 position of methyl pyropheophorbides-a, which is derived from naturally occurring chlorophyll(Chl)-a, were achieved by using N-fluorobenzenesulfonimide (NFSI). All the synthetic Chl-a derivatives possessing a variety of the C3-substituents (vinyl, ethyl, formyl, acetyl, hydroxymethyl, and 1-hydroxyethyl groups) were mono-fluorinated to produce the corresponding 20-fluoro-chlorins as isolated products. These fluorinated products were characterized by 1D/2D NMR, visible absorption, and fluorescence emission spectroscopy. Owing to the strong electronegativity of the C20-fluorine atom, their red-most Qy absorption and fluorescence emission bands were bathochromically shifted except for the C3-acetyl substitutes. This study showed not only tolerance of the chlorin π-skeleton and C3-substituents to NFSI but also potential availability of the fluorinated Chl library.
- Ogasawara, Shin,Nakano, Kohei,Tamiaki, Hitoshi
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- Synthetic substituted boronates of dihydroxy-bacteriochlorin absorbing and emitting far-red to near-infrared light as bacteriopheophytin-a analogs
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Several substituted boronates of methyl cis-7,8-dihydroxy-pyrobacteriopheophorbide-a possessing the same 3-acetyl-131-oxo-bacteriochlorin π-conjugated system as bacteriopheophytin-a found in type-II reaction centers of anoxygenic photosynthetic
- Funakoshi, Daichi,Nomura, Yosaku,Shoji, Sunao,Tamiaki, Hitoshi
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- Synthesis of a chlorophyll-a derivative fused with an additional exo-five-membered ring and its optical properties
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A C20-free chlorophyll-a derivative with an additional exo-five-membered ring was successfully prepared using an ethylene linkage at the C3- and C5-positions. A bromination at the C20-position was requisite for the cyclization of a 1-hydroxyethyl or vinyl group at the C3-position of methyl bacteriopheophorbide-d or methyl pyropheophorbide-a, respectively. By comparing optical properties of the cyclized product with those of its 3-ethyl uncyclized analog in a diluted dichloromethane solution, it was shown that the cyclization shifted the Qx and Bx absorption maxima to longer wavelengths and reduced the Stokes shift.
- Doi,Tamiaki, Hitoshi
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- Synthesis of Cationic Pyridinium-(Bacterio)Chlorophyll Conjugates Bearing a Bacteriochlorin, Chlorin, or Porphyrin π-Skeleton and their Photophysical and Electrochemical Properties
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Fine-tuning the electronic absorption properties of chlorophylls is important for their use as light-absorbing pigments. By oxidative coupling, a cationic pyridinium group was selectively introduced at the peripheral vinyl group of three types of synthetic chlorophylls with different degrees of π-conjugation of the cyclic tetrapyrroles (bacteriochlorin, chlorin, and porphyrin). The substitution with the electron-withdrawing pyridinium group moved redmost electronic absorption and main fluorescence emission maxima to longer wavelengths. This substitution effect depended on the core π-system and decreased with increasing the degree of dehydrogenation of the cyclic tetrapyrrole (bacteriochlorin ' chlorin ' porphyrin). Moreover, fluorescence quenching was observed as a consequence of the introduction of the pyridinium group. The electrochemical measurements and theoretical model calculations showed that the quenching is ascribed to an intramolecular electron transfer from the core π-skeleton to the peripheral cationic pyridinium group.
- Takahashi, Tatsuya,Ogasawara, Shin,Shinozaki, Yoshinao,Tamiaki, Hitoshi
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p. 6333 - 6340
(2019/09/06)
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- Tumor size-dependent anticancer efficacy of chlorin derivatives for photodynamic therapy
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Photodynamic therapy (PDT) with a suitable photosensitizer molecule is a promising anticancer treatment. We evaluated two chlorin molecules as potential photosensitizers, methyl pyropheophorbide a (MPPa) and N-methoxyl purpurinimide (NMPi), against A549 human lung adenocarcinoma cells in vitro as well as in A549 tumor-bearing mice in vivo. Cell viability, microscopy, and fluorescence-activated cell sorting (FACS) analyses were performed for the in vitro studies. MPPa and NMPi showed high phototoxicity in vitro, which was dependent on the concentration of the photosensitizers as well as the light irradiation time. In the animal study, tumor volume change, tumor surface alterations, and hematoxylin & eosin (H&E) and terminal deoxyribonucleotidyl transferse-mediated dUTP nick-end labelling (TUNEL) staining analyses were performed and compared between small (tumor volume of 3) and large (tumor volume of >50 mm3) size of initial tumors. MPPa and NMPi showed high anticancer efficacy against small-size tumors, indicating that early treatment with PDT is effective. Especially, repeated two times PDT with NMPi allowed almost complete eradication against small-size tumors. However, MPPa and NMPi were not effective against large-size tumors. In conclusion, the two chlorin derivatives, MPPa and NMPi, show good anticancer efficacy as promising photosensitizers for PDT in vitro and in vivo. Moreover, their activity in vivo was significantly dependent on the initial tumor size in mice, which confirms the importance of early cancer treatment.
- Chang, Ji-Eun,Liu, Yang,Lee, Tae Heon,Lee, Woo Kyoung,Yoon, Il,Kim, Kwhanmien
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- Semi-synthesis and HPLC analysis of (bacterio)chlorophyllides possessing a propionic acid residue at the C17-position
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Various chlorophyll and bacteriochlorophyll derivatives possessing a magnesium or zinc atom at the central position and a free carboxylic acid group at the C172-position, also known as (bacterio)chlorophyllides, were synthesized through a combination of organic synthesis techniques and enzymatic steps. The semi-synthetic (bacterio)chlorophyllides were purified and analyzed using reversed-phase high-performance liquid chromatography with UV-vis spectroscopy and mass spectrometry. These free propionic acid-containing chlorophyllous pigments can be useful research materials for the study of (bacterio)chlorophyll metabolisms.
- Teramura, Misato,Tamiaki, Hitoshi
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p. 423 - 436
(2018/03/21)
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- NANOVESICLES COMPRISING PORPHYRIN-LIPID CONJUGATES EXHIBITING ORDERED ASSEMBLY AND BATHOCHROMIC SHIFTS
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The application relates to liposomal nanovesicles comprising porphyrin-lipid conjugates within the liposomal lipid bilayer. Said porphyrin-lipid conjugate comprise porphyrins that are modified with a -CH(R1)-O-R2 group and that chelate a metal ion. Such modifications of the porphyrin allow for ordered assembly in the lipid bilayer of the nanovesicles while resulting in a bathochromic shift in the wavelength of light absorbed by the porphyrin chromophore. These nanovesicles can be used for photothermal therapy, photodynamic therapy, photoacoustic imaging and fluorescence imaging. The application also teaches methods for preparing the porphyrin-lipid conjugates and the nanovesicles.
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(2017/10/18)
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- Synthesis of monovinyl- and divinyl-chlorophyll analogs and their physical properties
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Chlorophyll-a was chemically modified to methyl pyropheophorbides-a possessing 3,8-diethyl, 3-vinyl-8-ethyl, 3-ethyl-8-vinyl, and 3,8-divinyl groups. Analogous 3-ethyl-7-vinyl- and 3,7-divinyl-chlorins were prepared by derivatization of chlorophyll-b. The synthetic free bases as well as zinc 3-vinyl-chlorins were dissolved in THF and the monomeric diluted solutions were characterized by optical spectroscopy including visible absorption, circular dichroism, and fluorescence emission spectra. The optical data indicated that the 3-vinylation bathochromically shifted the visible (Soret/Qx/Qy) absorption and fluorescence emission maxima, the 7-vinylation moved the Soret/Qx and Qy/emission bands to longer and slightly shorter wavelengths, respectively, and the 8-vinylation induced red shifts of the Soret/Qx maxima and no (or faint red) shifts of the Qy/emission maxima. Zinc complexes of 3,7- and 3,8-divinyl-chlorins showed almost the same optical properties including fluorescence emission quantum yields and lifetimes as well as the same first oxidation potentials, thus, 3,7-divinyl-chlorophyll-a could be considered an alternative pigment to the naturally occurring 3,8-divinyl analog.
- Kim, Kifa,Tsuji, Kazuki,Kinoshita, Yusuke,Miyatake, Tomohiro,Tamiaki, Hitoshi
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p. 313 - 321
(2017/01/03)
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- Preparation of mono-vinylated and formylated chlorophyll derivatives and their optical properties
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Regioisomeric 3- and 8-vinylchlorins as well as 7- and 12-vinylchlorins were prepared by modifying naturally occurring chlorophylls-a and/or b. The corresponding formylchlorins were synthesized by oxidation of the 3/8-vinyl, 7-hydroxymethyl or 12-methyl groups and readily transformed to the vinylchlorins by Wittig reactions. Their visible absorption, circular dichroism, fluorescence emission spectra in dichloromethane were dependent on the substituents directly conjugated with a chlorin π-system. The substitution with vinyl and formyl groups at the 3- and 12-positions on a molecular y-axis shifted redmost Qy absorption maxima to longer wavelengths than those at 7/8-positions on an?x-axis. The synthetic vinylchlorins were more fluorescent than the corresponding formylchlorins.
- Tamiaki, Hitoshi,Tsuji, Kazuki,Kim, Kifa,Miyatake, Tomohiro
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p. 4368 - 4376
(2016/07/06)
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- Synthesis of chlorophyll-a derivatives methylated in the 3-vinyl group and their intrinsic site energy
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Wittig reaction of methyl pyropheophorbide-d possessing the 3-formyl group gave readily methyl pyropheophorbides-a bearing a variety of 3-alkenyl groups as semi-synthetic models of chlorophyll-a. The 3-substituents rotated around the C3-C31 bond from the coplanar conformation with the chlorin π-system, moving the redmost visible absorption maxima to a shorter wavelength. The model experiments showed that natural chlorophyll-a carrying the 3-vinyl group would take a similar rotamer to control its intrinsic site energy.
- Tamiaki, Hitoshi,Tsuji, Kazuki,Kuno, Masaki,Kimura, Yuki,Watanabe, Hiroaki,Miyatake, Tomohiro
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supporting information
p. 3034 - 3037
(2016/06/13)
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- Synthesis of chlorins by Diels-Alder cycloadditions of pheophorbide a and its derivatives
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The Diels-Alder reaction was exploited for the preparation of novel long-wavelength chlorin photodynamic therapy photosensitizers. The styryl group and furan carboxamide substituents were used as diene components in [4+2] cycloaddition functionalizations.
- Bri?, Anamarija,Marini?, ?eljko,Chen, Zhi-Long,Margeti?, Davor
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supporting information
p. 991 - 994
(2015/04/27)
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- Convenient peripheral aroyloxylation reactions of porphyrins and chlorophyll-a-based chlorins with benzoyl peroxide
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A practical and efficient methodology for the formation of C-O bonds on the porphyrin/chlorin periphery was developed. The aroyloxy-substituted porphyrins and chlorins related to chlorophyll-a at the β- and meso-positions, respectively, were conveniently synthesized by the free radical substitution reaction with benzoyl peroxide and its homologs.
- Li, Jiazhu,Zhang, Peng,Yao, Nan-Nan,Zhao, Li-Li,Wang, Jin-Jun,Shim, Young Key
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p. 1086 - 1089
(2015/02/18)
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- Phototoxic effects of pyropheophorbide-a from chlorophyll-a on cervical cancer cells
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Photodynamic therapy (PDT) is a promising modality in both the curative and palliative treatment against a variety of experimental and naturally occurring human cancers. At present, chlorophyll a derivatives are extensively used for the synthesis of photosensitizers (PSs) for PDT of tumors. In the present study, chlorophyll-a was extracted from the blue-green algae Spirulina platensis by refluxing with acetone. The extract was further acid treated to obtain methylpheophorbide-a (MPa), which was then refluxed in collidine and methylpyropheophorbide-a (Mppa) was obtained. After that, Mppa was converted to pyropheophorbide-a (Ppa) by treatment with 50% sulfuric acid. Finally, phototoxicity and dark toxicity of purified Ppa in two different cell lines, TC-1 and CaSki, were examined by MTT assay. The results suggest that Ppa is more toxic to TC-1 cell line than CaSki cell line. In vivo, the photosensitizing efficiency of Ppa was also higher than those of unloaded PS. These results indicate the potential of Ppa in PDT.
- Chaturvedi, Pankaj Kumar,Kim, Yong-Wan,Kim, Sang Soo,Ahn, Woong Shick
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p. 182 - 187
(2014/05/20)
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- Convenient peripheral aroyloxylation reactions of porphyrins and chlorophyll-a-based chlorins with benzoyl peroxide
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A practical and efficient methodology for the formation of C-O bonds on the porphyrin/chlorin periphery was developed. The aroyloxy-substituted porphyrins and chlorins related to chlorophyll-a at the β- and meso-positions, respectively, were conveniently synthesized by the free radical substitution reaction with benzoyl peroxide and its homologs.
- Li, Jiazhu,Zhang, Peng,Yao, Nan-Nan,Zhao, Li-Li,Wang, Jin-Jun,Shim, Young Key
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p. 1086 - 1089
(2014/02/14)
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- Synthesis of chlorophyll-f analogs possessing the 2-formyl group by modifying chlorophyll-a
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A methyl group at the 2-position of methyl mesopyropheophorbide-a was transformed to the 2-formyl group to give methyl mesopyropheophorbide-f, one of the chlorophyll-f analogs. The 2-formylation moved the redmost electronic absorption band in a solution to a longer wavelength and the bathochromic shift was comparable to that by the 3-formylation. Zinc complex of the synthetic compound in solutions showed similar visible absorption spectra as those of naturally occurring chlorophyll-f.
- Xu, Meiyun,Kinoshita, Yusuke,Tamiaki, Hitoshi
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supporting information
p. 3997 - 4000
(2014/09/03)
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- Double helices of a pyridine-appended zinc chlorophyll derivative
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Self-assembled structures formed from a pyridine-appended zinc chlorophyll derivative are reported. While the zinc complex forms cyclic oligomers in chloroform solution, as indicated by 1H NMR studies (including diffusion-ordered spectroscopy), vapor pressure osmometry, and cold-spray ionization mass spectrometry, it forms double-stranded helical coordination polymers in the solid state, as revealed by single-crystal X-ray analysis.
- Shinozaki, Yoshinao,Richards, Gary,Ogawa, Keizo,Yamano, Akihito,Ohara, Kazuaki,Yamaguchi, Kentaro,Kawano, Shin-Ichiro,Tanaka, Kentaro,Araki, Yasuyuki,Wada, Takehiko,Otsuki, Joe
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supporting information
p. 5262 - 5265
(2013/06/04)
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- Synthesis of 3,20-disubstituted chlorophyll-a derivatives and reactivity of the substituents
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Methyl 20-bromo-pyropheophorbide-a possessing a vinyl group at the 3-position and its analogs having 3-ethyl, 3-(1-hydroxyethyl) and 3-acetyl groups were prepared by modifying naturally occurring chlorophyll(Chl)-a. The 20-bromo-chlorins were cross-coupled with vinyl- and 1-ethoxyvinyl-tributyltins in the presence of a Pd(0) catalyst to afford 20-vinyl- and acetyl-chlorins, respectively. The interconversions among the above four C2-functional groups at the 3-position were readily performed in the semi-synthetic Chl derivatives, but no modification of the 20-vinyl and acetyl groups was observed. The difference of the chemical reactivity is ascribable to the steric factor: the 3 1-position was less sterically hindered than the 20 1-position. Single hydrogenation and hydration of 3,20-divinyl-chlorin and reduction of 3,20-diacetylchlorin proceeded exclusively at the 3-position. The redmost (Qy) bands in electronic absorption spectra of the semi-synthetic Chl derivatives in a diluted dichloromethane solution were controlled by the 3,20-substituents. The 3-substituent effect on their Qy maxima was determined by the electronic factor (their electronegativity), while the 20-substituent effect was primarily dependent on the steric factor (their local size).
- Tamiaki, Hitoshi,Ariki, Nobutaka,Sugiyama, Haruka,Taira, Yoshichika,Kinoshita, Yusuke,Miyatake, Tomohiro
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p. 8412 - 8421
(2013/09/02)
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- Efficient two-electron reduction of dioxygen to hydrogen peroxide with one-electron reductants with a small overpotential catalyzed by a cobalt chlorin complex
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A cobalt chlorin complex (CoII(Ch)) efficiently and selectively catalyzed two-electron reduction of dioxygen (O2) by one-electron reductants (ferrocene derivatives) to produce hydrogen peroxide (H 2O2) in the presence of perchloric acid (HClO4) in benzonitrile (PhCN) at 298 K. The catalytic reactivity of Co II(Ch) was much higher than that of a cobalt porphyrin complex (CoII(OEP), OEP2- = octaethylporphyrin dianion), which is a typical porphyrinoid complex. The two-electron reduction of O2 by 1,1′-dibromoferrocene (Br2Fc) was catalyzed by Co II(Ch), whereas virtually no reduction of O2 occurred with CoII(OEP). In addition, CoII(Ch) is more stable than CoII(OEP), where the catalytic turnover number (TON) of the two-electron reduction of O2 catalyzed by CoII(Ch) exceeded 30000. The detailed kinetic studies have revealed that the rate-determining step in the catalytic cycle is the proton-coupled electron transfer reduction of O2 with the protonated CoII(Ch) ([CoII(ChH)]+) that is produced by facile electron-transfer reduction of [CoIII(ChH)]2+ by ferrocene derivative in the presence of HClO4. The one-electron-reduction potential of [CoIII(Ch)]+ was positively shifted from 0.37 V (vs SCE) to 0.48 V by the addition of HClO4 due to the protonation of [CoIII(Ch)]+. Such a positive shift of [Co III(Ch)]+ by protonation resulted in enhancement of the catalytic reactivity of [CoIII(ChH)]2+ for the two-electron reduction of O2 with a lower overpotential as compared with that of [CoIII(OEP)]+.
- Mase, Kentaro,Ohkubo, Kei,Fukuzumi, Shunichi
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supporting information
p. 2800 - 2808
(2013/03/29)
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- Systematic analysis of the demetalation kinetics of zinc chlorophyll derivatives possessing different substituents at the 3-position: Effects of the electron-withdrawing and electron-donating strength of peripheral substituents
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Removal of the central metal from chlorophyll (Chl) molecules is biologically important in terms of production of the primary electron acceptors in photosystem-II photosynthetic reaction centers and the early stage in Chl degradation. The physicochemical properties on demetalation of chlorophyllous pigments are useful in the understanding of such reaction mechanisms in photosynthetic organisms. Here we analyzed the demetalation kinetics of a series of Zn-Chl derivatives with a systematic variation in the electron-withdrawing and -donating substituents at the 3-position of the chlorin macrocycle under acidic conditions to elucidate thoroughly the substitution effects on the demetalation properties of chlorophyllous pigments. Dehydrogenation of the aliphatic group (CH2CH3 → CH-CH2 → C? - CH) at the 3-position slowed the removal of the central zinc from the chlorin macrocycle. The gradual decrease in the demetalation rate constants of the three zinc chlorins originates from differences in the electron-withdrawing strength of the ethyl, vinyl, and ethynyl groups directly linked to the chlorin π macrocycle. Reduction of the 31-carbonyl groups significantly increased the demetalation rate constants, and the relative ratios of the demetalation rate constants of the zinc chlorins possessing a carbonyl group to those possessing the corresponding hydroxy group were analogous in the cases of 3-formyl- and 3-acetyl-zinc chlorins. The demetalation rate constants of the seven Zn-Chl derivatives possessing various electron-withdrawing and -donating groups exhibited good correlation with the Hammett σ parameters of the 3-position substituents.
- Saga, Yoshitaka,Kobashiri, Yuta,Sadaoka, Kana
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p. 204 - 210
(2013/02/23)
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- Synthesis, photophysical and electrochemistry of near-IR absorbing bacteriochlorins related to bacteriochlorophyll a
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A series of new bacteriochlorins was synthesized using 13 2-oxo-bacteriopyropheophorbide a (derived from bacteriochlorophyll a) as a starting material, which on reacting with o-phenylenediamine and 1,10-diaminonaphthalene afforded highly conjug
- Kozyrev, Andrei,Ethirajan, Manivannan,Chen, Ping,Ohkubo, Kei,Robinson, Byron C.,Barkigia, Kathleen M.,Fukuzumi, Shunichi,Kadish, Karl M.,Pandey, Ravindra K.
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p. 10260 - 10271
(2013/01/15)
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- Modification of 3-substituents in (bacterio)chlorophyll derivatives to prepare 3-ethylated, methylated, and unsubstituted (nickel) pyropheophorbides and their optical properties
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Methyl mesopyropheophorbide-a possessing an ethyl group at the 3-position, its 31-demethyl analogue (3-methyl homologue), and its 3 1-deethyl analogue (3-unsubstituted chlorin) were prepared by modifying naturally occurring (bacterio)chlorophylls bearing 3-vinyl, formyl, acetyl, and 1-hydroxyethyl groups. These synthetic 3-(un)substituted chlorophyll derivatives and their nickel complexes are probable intermediates during degradation of (bacterio)chlorophylls to chemically stable porphyrinoids. The optical properties (visible absorption, circular dichroism, and fluorescence emission) of the catabolic candidates in a solution were measured, and the substitution effect was investigated.
- Tamiaki, Hitoshi,MacHida, Shinnosuke,Mizutani, Keisuke
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p. 4751 - 4758
(2012/07/14)
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- TSPO 18 kDa (PBR) targeted photosensitizers for cancer imaging (PET) and PDT
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Translocator protein (TSPO) 18 kDa overexpression has been observed in a large variety of human cancers, especially breast cancers. PK 11195, an isoquinoline analogue, is one of the ligands of highest TSPO binding affinity. Due to the long biological half
- Chen, Yihui,Sajjad, Munawwar,Wang, Yanfang,Batt, Carrie,Nabi, Hani A.,Pandey, Ravindra K.
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scheme or table
p. 136 - 141
(2011/04/15)
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- Synthesis of potential antitumor agents, dimeric and trimeric chlorins, from methylpheophorbide a
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A series of dimeric and trimeric chlorins were synthesized from methylpheophorbide a. They are potential photosensitizers for photodynamic therapy in oncology. The macrocycles were conjugated due to the formation of ester and amide bonds. The carboxy groups were activated and catalytic transesterification was carried out to form the ester bond. The amide bond was formed using carboxy group activation; in several cases, amidation of the ester group in position 13(2) of the exocycle of methylpheophorbide α was carried out, which does not require activation.
- Belykh,Mal'Shakova,Yudina,Zavadskaya,Khudyaev,Kuchin
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scheme or table
p. 719 - 728
(2012/02/05)
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- Synthesis and optical properties of C3-ethynylated chlorin and π-extended chlorophyll dyads
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A C3-ethynylated chlorophyll derivative was prepared from methyl pyropheophorbide-d possessing a 3-formyl group by treatment of Bestmann-Ohira reagent. The mono-substituted acetylene was subjected to coupling reactions at the terminal acetylenic carbon at
- Sasaki, Shin-Ichi,Mizutani, Keisuke,Kunieda, Michio,Tamiaki, Hitoshi
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scheme or table
p. 6065 - 6072
(2011/09/12)
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- Opening of the extra ring in pheophorbide a methyl ester by the action of amines as a one-step method for introduction of additional fragments at the periphery of chlorin macroring
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Opening of the extra ring in pheophorbide a methyl ester by the action of amines differing in the number, size, and structure of substituents on the nitrogen atom was studied with a view to synthesize chlorine e 6 13-carboxamides. Main factors restricting one-step preparation of 13-carboxamides with a desired substituent were revealed. The obtained experimental data can be used as a basis for predicting the possibility for onestep preparative synthesis of particular chlorin e 6 13-carboxamide via reaction with one or another amine.
- Belykh,Kopylov,Gruzdev,Kuchin
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scheme or table
p. 577 - 585
(2010/09/05)
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- Synthesis of isoxazoline-linked chlorins and their in vitro cell viabilities
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A concise synthesis of isoxazoline-linked chlorins is described. This approach is carried out from methyl pyropheophorbide-a as the starting material via 1,3-dipolar cycloaddition of a vinyl group on the periphery with nitrile oxide to give regioselective
- Wang, Jin-Jun,Li, Jia-Zhu,Li, Yun-Wei,Jakus, Judit,Shim, Young Key
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scheme or table
p. 859 - 865
(2011/12/01)
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- Peroxide decoloration of CI acid orange 7 catalyzed by manganese chlorophyll derivatives at the surfaces of micelles and lipid bilayers
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Manganese-substituted chlorophyll a derivatives (MnChls) were synthesized. We first report peroxidative oxidation of an azo dye, CI Acid Orange 7, catalyzed by MnChls at the surfaces of micelles and lipid bilayers with hydrogen peroxide (H2O2) under mild conditions (pH 8.0, 25 °C). Peroxide decoloration depended upon the structures of MnChls, surfactants, lipids, and the presence of imidazole. Surprisingly, a largest decoloration rate was observed for MnChls dimer, MnPChlide a-K(MnPChlide a)-His 5 in cetyltrimethylammonium bromide (CTAB) micellar solution, especially when imidazole was present: this observation is analogous to the decoloration using horseradish peroxidase (HRP). Interestingly, the dimer complexes showed enhanced decoloration in comparison to the corresponding MnChls monomer in the micellar solution. In contrast, the MnChls monomer showed enhanced decoloration in comparison with the MnChls dimer in liposomal suspensions. Further, the imidazole residue covalently linked to the MnChls plays an important role in increasing the decoloration in both micellar and liposomal suspensions as well as in addition of imidazole into the solutions. It is interesting that the electron paramagnetic resonance (EPR) spectra of MnPChlide a ME 2, MnPChlide a-His 3, and MnMPMME-His 7 have 16 peaks around g = 2 in Egg PC or DMPC liposomal suspension with H2O2, which is typical of a mixed-valence Mn(III)-Mn(IV) complex with coupling between two ions. The higher decoloration performance obtained by the monomer porphyrin compounds at the surface of the lipid bilayers appears to be related to the stability of this mixed-valence Mn(III)-Mn(IV) species formed in the lipid bilayers. This finding should provide useful information to note that MnChls, which are easily found in a number of biological systems, are involved in functions such as hydrogen peroxide decomposition in bacteria and the oxidation of water during photosynthesis as well as the peroxidases function such as the peroxidative decoloration as bleaching agents.
- Ishigure, Shuichi,Mitsui, Tatsuro,Ito, Shingo,Kondo, Yuji,Kawabe, Shigeki,Kondo, Masaharu,Dewa, Takehisa,Mino, Hiroyuki,Itoh, Shigeru,Nango, Mamoru
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scheme or table
p. 7774 - 7782
(2011/12/15)
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- Structure-property relationships for self-assembled zinc chlorin light-harvesting dye aggregates
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A series of zinc 31-hydroxymethyl chlorins 10 a-e and zinc 31-hydroxyethyl chlorins 17 with varied structural features were synthesized by modifying naturally occurring chlorophyll a. Solvent-, temperature-, and concentration-depende
- Huber, Valerie,Sengupta, Sanchita,Wuerthner, Frank
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experimental part
p. 7791 - 7807
(2009/09/25)
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- Methyl pyropheophorbide-a analogues: Potential fluorescent probes for the peripheral-type benzodiazepine receptor. Effect of central metal in photosensitizing efficacy
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Pyropheophorbides and their metal complexes were synthesized to investigate their applications as nonradioactive peripheral benzodiazepine receptor (PBR) binding probes and photosensitizers for use in photodynamic therapy. They were found to be localized in mitochondria and showed significant binding to PBR. In some cases, the PBR binding values were similar to that for 17 (PK11195, 1-(2-chlorophenyl)-N-methyl-N-(1-methylpropyl)isoquinoline-3-carboxamide). However, no direct correlation between 17 displacement ability and photosensitizing efficacy of photosensitizers was observed.
- Chen, Yihui,Zheng, Xiang,Dobhal, Mahabeer P.,Gryshuk, Amy,Morgan, Janet,Dougherty, Thomas J.,Oseroff, Allan,Pandey, Ravindra K.
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p. 3692 - 3695
(2007/10/03)
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- ACTIVATABLE PHOTODYNAMIC THERAPY AGENTS
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The present invention relates to the field of conjugates comprising a first substrate which is attached to a least one photosensitizer and at least ont first quencher, and methods for their use. More particularly, the present invention relates to photodynamic therapy agents. The invention further relates to methods for decontaminating blood and methods for treating cancer or viral infection in a subject using the conjugates of the present invention.
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Page/Page column 31; 32
(2008/06/13)
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- Syntheses and optical properties of stable 8-alkylidene-bacteriochlorins mimicking the molecular structures of natural bacteriochlorophylls-b and g
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We prepared bacteriochlorophyll(BChl)-b and g models by Diels-Alder reactions of 8-vinyl-chlorophylls with tetracyanoethylene. The resulting 8-alkylidene-bacteriochlorins with various substituent groups at the 3-position had the same π-conjugate as BChls-b/g. While the natural pigments isomerized by addition of an acid to afford the corresponding chlorins, the synthetic models were stable under the acidic conditions due to dialkylation at the 7-position. These BChl-b/g models are useful for investigating the optical properties of relatively unstable BChls-b/g. Chemically stable 8-alkylidene-bacteriochlorins were systematically prepared as models of natural bacteriochlorophylls-b/g easily isomerizing to the corresponding chlorins, and their optical properties were investigated in detail.
- Kunieda, Michio,Mizoguchi, Tadashi,Tamiaki, Hitoshi
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p. 11349 - 11357
(2007/10/03)
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- Antitumor agents. Part 209: Pheophorbide-a derivatives as photo-Independent cytotoxic agents.
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A methanolic crude extract of the plant Garuga pinnata Roxb. (Burseraceae) showed promising cytotoxic activity against a panel of human tumor cell lines in vitro, including KB and its drug-resistant sublines (Ferguson et al. Cancer Res. 1988, 48, 5956). Pheophorbide-a and-b methyl esters (3,4) were isolated as active principles with broad photo-dependent cytotoxic activities in the micromolar range. These findings prompted SAR studies of known and novel pheophorbide-a derivatives as photo-dependent and photo-independent cytotoxic agents. The results showed that zinc-protoporphyrin IX (10), zinc 13(R)-hydroxypheophorbide-a methyl ester (22), and zinc chlorin-e6 trimethyl ester (13) possessed photo-independent cytotoxic activity. Compounds 13 and 22 were the most active cytotoxic agents of the series (mean ED(50) 4.6 +/- 1.0 microM and 5.7 +/- 0.7 microM, respectively) against KB cells incubated in the dark.
- Wongsinkongman, Prapai,Brossi, Arnold,Wang, Hui-Kang,Bastow, Kenneth F,Lee, Kuo-Hsiung
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p. 583 - 591
(2007/10/03)
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- Synthesis and self-aggregation of zinc chlorophylls possessing an ω-hydroxyalkyl group: Effect of distance between interactive hydroxy group and chlorin moiety on aggregation
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Zinc 131-oxochlorins 2,3 and 3D possessing 2-hydroxyethyl, 3-hydroxypropyl and 3-hydroxyprop-1-enyl groups, respectively, at the 3-position are synthesized as models for self-aggregative antenna chlorophylls in green photosynthetic bacteria. Self-aggregation of 2,3 and 3D in nonpolar organic solvents and in the solid state is compared with that of 1 possessing a 3-hydroxymethyl group to determine the effect of the distance between the hydroxy group and the chlorin moiety on the self-aggregation. Visible spectral analyses in hexane containing a small amount of THF reveal that the aggregation abilities decrease in the order of 1 → 2 → 3, with an increase of conformational flexibility of the ω-hydroxyalkyl group in a molecule. Aggregated 2 and 3 give absorption maxima at 701 and 702 nm, respectively, red-shifted from the corresponding monomeric absorption (644 nm). These red-shifts are smaller than that of 1 (647 → 740 nm), which is attributable to the expanded chlorin π-π plane distance in the self-aggregates of 2 and 3. Furthermore, their CD and IR spectra reveal that the aggregates of 3 are relatively disordered and have weak intermolecular noncovalent interactions among the hydroxy group, central zinc and keto group in the supramolecule. Aggregated 3D shows a relatively small red-shift of absorption from monomer to aggregates (654 → 680 nm) due to the decreased overlap between the chlorin π-planes in the aggregated state. However, 3D easily forms precipitates composed of structurally ordered large aggregates, indicating that 3D is favorable for molecular packing in the aggregates.
- Yagai, Shiki,Tamiaki, Hitoshi
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p. 3135 - 3144
(2007/10/03)
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