meso-Phenyl substituted porphocyanines: A new class of functionalized expanded porphyrins

Boyle, Ross W.; Xie, Lily Y.; Dolphin, David

doi:10.1016/s0040-4039(00)73504-0

Cited by 40 publications

(26 citation statements)

References 8 publications

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“…The pentafluorobenzaldehyde has been applied in research of new materials in porphyrin chemistry [111,184,, chemistry of corroles (58 [442][443][444][445][446][447][448][449][450][451][452][453][454][455]), porphocyanines (60) and their precursors (59 [456][457][458][459][460][461] of porphyrins (61), which are utilizable in many fields of chemistry (Scheme 38 [348,[462][463][464][465][466][467]). Along this line, the synthesis of expanded porphyrin cyclescalixphyrines is interesting too (62, Scheme 39 [468][469][470]).…”

Section: Chemical Reactions Of Pentafluorobenzaldehyde With Carbon Numentioning

confidence: 99%

Pentafluorobenzaldehyde and its utilizing in organic synthesis

Pažitný

Solčan

Végh

2009

Journal of Fluorine Chemistry

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Section: Chemical Reactions Of Pentafluorobenzaldehyde With Carbon Numentioning

confidence: 99%

Pentafluorobenzaldehyde and its utilizing in organic synthesis

Pažitný

Solčan

Végh

2009

Journal of Fluorine Chemistry

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“…m/z (FAB) 444 (M + +1). Anal.Calcd for C 25 H 19 BrN 4 :C, 65.02; H,4.32;N,12.62 Found: C,65.23;H,4.39;N,12.76. (1H-pyrrol-2-yl)methyl]-3-(2-thienyl)-1H-pyrazole (3j) White crystalline solid; Mp 150-152 o C; yield 89%; ν max (KBr) 3386 cm -1 ; δ H (200 MHz, CDCl 3 ) 5.64 (s, 1H, CH), 6.01-6.02 (m, 2H, pyrrolyl), 6.…”

Section: -[4-bromophenyl]-4-[di(1h-pyrrol-2-yl)methyl]-1-phenyl-1h-pmentioning

confidence: 99%

“…Earlier, 5-aryldipyrromethanes, used as a precursor for the synthesis of porphyrins have been synthesized [9][10][11][12][13][14] by the reaction of aldehydes with excess of pyrrole in the *Address correspondence to this author at the Medicinal and Process Chemistry Division, Central Drug Research Institute Lucknow 226001, India; Tel: +91 522 2960779; Fax: +91 522 2623 405; E-mail: vjiram@yahoo.com presence of catalytic amount of acid to suppress the side reaction of polymerization. Nagarkatti and Ashley [9] reported first the synthesis of 4-pyridyldipyrromethane by condensation of 4-pyridylcarboxaldehyde and pyrrole in acidified methanol.…”

Section: Introductionmentioning

confidence: 99%

An Efficient and Concise Synthesis of Heteroaryldipyrromethanes, Tetrapyrazolylporphyrins and Metalloporphyrins

Farhanullah¹,

Ram²

2009

TOOCJ

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One pot synthesis of terpyrromethanes (3a) and [di(1H-pyrrol-2-yl)methyl]heteroarenes (3b-m) has been delineated by Amberlyst 15 catalyzed condensation of pyrrole and heterocyclic aldehydes (2), not reported earlier. The compounds 3a and 3b have been formylated to 5-[di(5-formyl-1H-pyrrol-2-yl)methyl]-1H-pyrrole-2-carbaldehyde (4a) and 5-[(5-formyl-1H-pyrrol-2-yl)(3-pyridinyl)methyl]-1H-pyrrole-2-carbaldehyde (4b), by using a mixture of POCl 3 and DMF as formylating agent. Similarly, 5-alkyl-1H-pyrrole-2-carbaldehyde (8) has also been prepared from 2-alkyl-1H-pyrroles (6), obtainable by acylation followed by Wolf-Kishner reduction. Amberlyst 15 / TFA catalyzed the condensation of 8 with pyrrole which gave 3a instead of expected product 10, due to an unusual cleavage of alkyl substituent at position 5 in 8. CS 2 addition to 6 followed by methylation provided methyl 5-alkyl-1H-pyrrole-2-carbodithioates (7), which on reaction with hydrazine hydrate yielded 5-alkyl-1H-pyrrole-2-carbothiohydrazide (9). Tetrapyrazolylporphyrins (12) have been synthesized directly by condensation of pyrrole with 3-aryl-4-formyl-1-phenylpyrazole (11) in propionic acid. These porphyrins were transformed to metalloporphyrins (13) from reaction with zinc and copper acetate separately.

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“…We recently communicated the synthesis and characterization of a new class of tetrapyrrolic macrocycles, porphocyanines 1 (1)(2)(3), and showed that these compounds were capable of catalyzing the photosensitized oxidation of cholesterol (3). They are potential photosensitizers for photodynamic therapy for cancer treatment because they offer long-wavelength absorption between 795 and 810 nm in their free base form, which would in principle confer superior tissue penetration to visible light than is the case with existing drugs.…”

Section: [Traduit Par La Rkdaction]mentioning

confidence: 99%

“…2, K3 could be obtained from the following eq. [3] (14) where A, and A, are the absorbances of the pure free base and pure monocation of the octaethylporphocyanine at 798 nm, and A is that of a mixture of monocation and free base at this specific wavelength. The data for the pH values and absorbance~ necessary for the calculation of K3 are given in Table 1.…”

Section: Wavelength ( N M )mentioning

confidence: 99%

Protonation of porphocyanine – a new expanded tetrapyrrolic macrocycle

Xie¹,

Dolphin²

1995

Can. J. Chem.

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The porphocyanine nucleus contains six nitrogen atoms, four of which are theoretically capable of accepting a proton in acidic solution. However, only the monoprotonated and diprotonated forms have been observed. These two forms were characterized by their visible and fluorescence spectra. pK, values of 6.0 L 0.1 and 4.4 ? 0.1 were determined by spectrophotometric titration. The monoprotonated monocationic form can be observed in methanol.Key words: porphocyanine, protonation, octaethylporphocyanine, octaethylporphyrin. Mots clis : porphocyanine, protonation, octakthylporphocyanine, octakthylporphyrine. [Traduit par la rkdaction]We recently communicated the synthesis and characterization of a new class of tetrapyrrolic macrocycles, porphocyanines 1 (1-3), and showed that these compounds were capable of catalyzing the photosensitized oxidation of cholesterol (3). They are potential photosensitizers for photodynamic therapy for cancer treatment because they offer long-wavelength absorption between 795 and 810 nm in their free base form, which would in principle confer superior tissue penetration to visible light than is the case with existing drugs. It is important to know the nature of the ionic species of a photosensitizer in solution as a function of pH (4), since it is known that the longest wavelength absorption and fluorescence emission are affected by protonation of the porphocyanine nucleus, which contains four potential sites for protonation. Furthermore, protonation of porphocyanine might effect biodistribution of the photosensitizer in vivo (4-7) Finally, the pK, data of porphocyanines are valuable in understanding the reactivity and aromaticity of this new macrocycle.It is of interest to compare the protonation properties of the porphocyanine with those of porphyrin (2), azaporphyrin (3), sapphyrin (4), and phthalocyanine (5). Several techniques have been used in the measurement of pK, values of porphyrins and related compounds taking account of their poor solubility in water, i.e., potentiometric titration in glacial acetic acid, and spectrophotometric titration in nitrobenzene and in aqueous detergent solutions (7-9). The pK, value of sapphyrin was, however, recently estimated using a spectrophotometric method in a biphasic system (10). ExperimentalOctaethylporphocyanine (H2P) was prepared according to the procedure described previously (1) and was dissolved in dichloromethane. The absorbance changes at specific wavelengths were monitored upon mixing a CH2C12 solution of octaethylporphocyanine (3.5 x l~-~ M) and a pH-adjusted aqueous NaCl solution ([Cl-],,,,, = 0.1 M). Electronic spectra were recorded on a Hewlett-Packard 8452A diode array spectrophotometer. The pH values were recorded on a Fisher Accumet pH meter model 210 with a glass combination electrode (Fisher Scientific). The pH meter was calibrated at 25°C with standard buffer solutions for pH 4.00 and 7.00 prior to the pH measurements. Fluorescence emission spectra were measured on an Aminco Bowman Series 2 luminescence spectrome...

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meso-Phenyl substituted porphocyanines: A new class of functionalized expanded porphyrins

Cited by 40 publications

References 8 publications

Pentafluorobenzaldehyde and its utilizing in organic synthesis

Pentafluorobenzaldehyde and its utilizing in organic synthesis

An Efficient and Concise Synthesis of Heteroaryldipyrromethanes, Tetrapyrazolylporphyrins and Metalloporphyrins

Protonation of porphocyanine – a new expanded tetrapyrrolic macrocycle

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