Refined syntheses of hydrodipyrrin precursors to chlorin and bacteriochlorin building blocks

Krayer, Michael; Balasubramanian, Thiagarajan; Ruzié, Christian; Ptaszek, Marcin; Cramer, David L.; Taniguchi, Masahiko; Lindsey, Jonathan S.

doi:10.1142/s1088424609001406

Cited by 39 publications

(75 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Thus, vicinal dibromination of known 1-formyldipyrromethane 3c gave Eastern half 3c-Br 8,9 (structure not shown), 18 which was used directly without further purification (Scheme 7). Condensation of 3c-Br 8,9 with bromo-Western half 71 5 gave 3,13-dibromochlorin 12 in 10% yield from 3c . Stille coupling 72 with tributyl(1-ethoxyvinyl)tin 73 and a catalytic amount of (Ph 3 P) 2 PdCl 2 in CH 3 CN/DMF (3:2) followed by acidic hydrolysis gave 3,13-diacetylchlorin 13 in 90% yield.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Bioconjugatable, PEGylated hydroporphyrins for photochemistry and photomedicine. Narrow-band, red-emitting chlorins

et al. 2016

Self Cite

View full text Add to dashboard Cite

Chromophores that absorb and emit in the red spectral region (600–700 nm), are water soluble, and bear a bioconjugatable tether are relatively rare yet would fulfill many applications in photochemistry and photomedicine. Here, three molecular designs have been developed wherein stable synthetic chlorins – analogues of chlorophylls – have been tailored with PEG groups for use in aqueous solution. The designs differ with regard to order of the installation (pre/post-formation of the chlorin macrocycle) and position of the PEG groups. Six PEGylated synthetic chlorins (three free bases, three zinc chelates) have been prepared, of which four are equipped with a bioconjugatable (carboxylic acid) tether. The most effective design for aqueous solubilization entails facial encumbrance where PEG groups project above and below the plane of the hydrophobic disk-like chlorin macrocycle. The chlorins possess strong absorption at ~400 nm (B band) and in the red region (Qy band); regardless of wavelength of excitation, emission occurs in the red region. Excitation in the ~400 nm region thus provides an effective Stokes shift of >200 nm. The four bioconjugatable water-soluble chlorins exhibit Qy absorption/emission in water at 613/614, 636/638, 698/700 and 706/710 nm. The spectral properties are essentially unchanged in DMF and water for the facially encumbered chlorins, which also exhibit narrow Qy absorption and emission bands (full-width-at-half maximum of each <25 nm). The water-solubility was assessed by absorption spectroscopy over the concentration range ~0.4 μM – 0.4 mM. One chlorin was conjugated to a mouse polyclonal IgG antibody for use in flow cytometry with compensation beads for proof-of-principle. The conjugate displayed a sharp signal when excited by a violet laser (405 nm) with emission in the 620–660 nm range. Taken together, the designs described herein augur well for development of a set of spectrally distinct chlorins with relatively sharp bands in the red region.

show abstract

Section: Resultsmentioning

confidence: 99%

“…80 Sonication was carried out using a benchtop sonication bath. Compounds 2c , 60 3c , 18 4 , 63 and 5 71 were prepared as described in the literature.…”

Section: Methodsmentioning

confidence: 99%

Bioconjugatable, PEGylated hydroporphyrins for photochemistry and photomedicine. Narrow-band, red-emitting chlorins

et al. 2016

Self Cite

View full text Add to dashboard Cite

show abstract

“…Streamlined procedures have been developed to convert pyrrole-2-carboxaldehyde to the desired bromo-tetrahydrodipyrrin with almost no chromatography, 285 thereby setting up access to the corresponding 3-substituted chlorins (Scheme 57). Thus, pyrrole-2-carboxaldehyde undergoes bromination regioselectively at the 4-position.…”

Section: Importance and Synthetic Challenges Of β-Pyrrole Substitumentioning

confidence: 99%

De NovoSynthesis of Gem-Dialkyl Chlorophyll Analogues for Probing and Emulating Our Green World

2015

Self Cite

View full text Add to dashboard Cite

Woodward reported his infamous synthesis of chlorin e 6 trimethyl ester, a known synthetic precursor to chlorophyll a. [59][60][61][62][63][64]124 The work was posited on a half-century of intensive studies by many investigators in tetrapyrrole chemistry and began a decade after the close of Fischer's lifetime of research 125−128 (which included an uncompleted synthetic program directed toward chlorophylls 15 ). Indeed, "he read all the umpteen papers on the chlorophylls written by Willstaẗter and Fischer, including the experimental parts." 129 The Woodward synthesis of chlorin e 6 trimethyl ester required 46 steps, of which 24 were spent on converting the sole precursor, Knorr's pyrrole, to the four pyrroles destined to form rings A−D; 7 additional steps accrued to obtain the dipyrromethanes that constitute the Eastern and Western halves (Scheme 13, the step numbers are identical to those shown in ref 64.). The first step formed the Knorr pyrrole (in several kg quantities), the next 24 steps were divided into four parallel paths, whereas the remaining 21 steps proceeded in linear fashion. Remarkable features of the synthesis include the directed intramolecular joining (via an imine) of the Eastern and Western halves (step 33), construction of the acrylate Scheme 10. Hydrogenation of a Porphyrin to Form a Chlorin Scheme 11. Representative meso-Tetraarylchlorins Scheme 12. Methyl Pyropheophorbide a

show abstract

“…Consequently, the synthesis of 13 was carried out, as a bromine substituent allows a range of possible synthetic transformations, particularly palladium catalysed cross coupling chemistry. 4-Bromopyrrole-2-carboxaldehyde (13) was obtained in good yield 48 and optimised fluorination conditions (Table 5) provided the desired product in 29 % yield.…”

Section: Resultsmentioning

confidence: 99%

Fluorination of pyrrole derivatives by Selectfluor™

Heeran

Sandford

2016

Tetrahedron

View full text Add to dashboard Cite

Additional information:Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details.

show abstract

Refined syntheses of hydrodipyrrin precursors to chlorin and bacteriochlorin building blocks

Cited by 39 publications

References 38 publications

Bioconjugatable, PEGylated hydroporphyrins for photochemistry and photomedicine. Narrow-band, red-emitting chlorins

Bioconjugatable, PEGylated hydroporphyrins for photochemistry and photomedicine. Narrow-band, red-emitting chlorins

De NovoSynthesis of Gem-Dialkyl Chlorophyll Analogues for Probing and Emulating Our Green World

Fluorination of pyrrole derivatives by Selectfluor™

Contact Info

Product

Resources

About