Physical and Theoretical Aspects of 1<i>H</i>‐Pyrroles

Chadwick, Derek J.

doi:10.1002/9780470187326.ch1

Cited by 4 publications

(2 citation statements)

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“…The literature data suggest that the values of the coupling constants between protons in the pyrrole ring can determine the positions of substituents (Chadwick 2008 ). Values in the range of 1.35–1.80 Hz can indicate the presence of substituents at positions C2 and C4, whilst in the case of substituents present at C2 and C3, these values are in the range of 2.40–3.10 Hz.…”

Section: Resultsmentioning

confidence: 99%

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Structural characterisation and pH-dependent preference of pyrrole cross-link isoforms from reactions of oxoenal with cysteine and lysine side chains as model systems

et al. 2023

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In this study, we subjected 5,5-diethoxy-4-oxopent-2-enal (DOPE), a model amino acids cross-linking reagent, to reactions with N-acetylcysteine (Ac-Cys) and Nα-acetyllysine (Ac-Lys), and identified three pyrrole cross-links. The compounds were isolated and their structures were rigorously determined by spectrometric and spectroscopic methods, including 2D NMR experiments. The use of 2D NMR spectroscopy was crucial to determine the position of the substituents in the pyrrole rings. The products were identified as 2,4-, 2,3-, and 2,5-substituted pyrroles. The data obtained from their structural characterisation can help similar studies on amino acids modifications induced by analogous bifunctional carbonyl compounds. Our results show that the study of pathways in which model electrophiles modify amino acids may be helpful for similar studies dealing with identification of structural changes in cysteine- and lysine-containing proteins associated with oxidative stress.

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Section: Resultsmentioning

confidence: 99%

“…Values in the range of 1.35–1.80 Hz can indicate the presence of substituents at positions C2 and C4, whilst in the case of substituents present at C2 and C3, these values are in the range of 2.40–3.10 Hz. The highest values (3.40–3.80 Hz) are observed for the pyrrole ring substituted at C2 and C5 (Chadwick 2008 ).…”

Section: Resultsmentioning

confidence: 99%

Structural characterisation and pH-dependent preference of pyrrole cross-link isoforms from reactions of oxoenal with cysteine and lysine side chains as model systems

et al. 2023

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Effect of catalyst surface on decomposition of nitrogen heterorings during regeneration of hydroprocessing catalysts

Furimsky¹

1998

Catalysis Today

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Regiospecifically α-¹³C-Labeled Porphyrins for Studies of Ground-State Hole Transfer in Multiporphyrin Arrays

et al. 2008

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Insight into the electronic communication between the individual constituents of multicomponent molecular architectures is essential for the rational design of molecular electronic and/or photonic devices. To clock the ground-state hole/electron-transfer process in oxidized multiporphyrin architectures, a p-diphenylethyne-linked zinc porphyrin dyad was prepared wherein one porphyrin bears two (13)C atoms and the other porphyrin is unlabeled. The (13)C atoms are located at the 1- and 9-positions (alpha-carbons symmetrically disposed to the position of linker attachment), which are sites of electron/spin density in the a(1u) HOMO of the porphyrin. The (13)C labels were introduced by reaction of KS(13)CN with allyl bromide to give the allyl isothiocyanate, which upon Trofimov pyrrole synthesis followed by methylation gave 2-(methylthio)pyrrole-2-(13)C. Reaction of the latter with paraformaldehyde followed by hydrodesulfurization gave dipyrromethane-1,9-(13)C, which upon condensation with a dipyrromethane-1,9-dicarbinol bearing three pentafluorophenyl groups gave the tris(pentafluorophenyl)porphyrin bearing (13)C labels at the 1,9-positions and an unsubstituted meso (5-) position. Zinc insertion, bromination at the 5-position, and Suzuki coupling with an unlabeled porphyrin bearing a suitably functionalized diphenylethyne linker gave the regiospecifically labeled zinc porphyrin dyad. Examination of the monocation of the isotopically labeled dyad via electron paramagnetic resonance (EPR) spectroscopy (and comparison with the monocations of benchmark monomers, where hole transfer cannot occur) showed that the hole transfer between porphyrin constituents of the dyad is slow (<10(6) s(-1)) on the EPR time scale at room temperature. The slow rate stems from the a(1u) HOMO of the electron-deficient porphyrins, which has a node at the site of linker connection. In contrast, analogous dyads of electron-rich porphyrins (wherein the HOMO is a(2u) and has a lobe at the site of linker connection) studied previously exhibit rates of hole transfer that are fast (>5 x 10(7) s(-1)) on the EPR time scale at room temperature.

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Physical and Theoretical Aspects of 1H‐Pyrroles

Cited by 4 publications

References 427 publications

Structural characterisation and pH-dependent preference of pyrrole cross-link isoforms from reactions of oxoenal with cysteine and lysine side chains as model systems

Structural characterisation and pH-dependent preference of pyrrole cross-link isoforms from reactions of oxoenal with cysteine and lysine side chains as model systems

Effect of catalyst surface on decomposition of nitrogen heterorings during regeneration of hydroprocessing catalysts

Regiospecifically α-¹³C-Labeled Porphyrins for Studies of Ground-State Hole Transfer in Multiporphyrin Arrays

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Physical and Theoretical Aspects of 1H‐Pyrroles

Cited by 4 publications

References 427 publications

Structural characterisation and pH-dependent preference of pyrrole cross-link isoforms from reactions of oxoenal with cysteine and lysine side chains as model systems

Structural characterisation and pH-dependent preference of pyrrole cross-link isoforms from reactions of oxoenal with cysteine and lysine side chains as model systems

Effect of catalyst surface on decomposition of nitrogen heterorings during regeneration of hydroprocessing catalysts

Regiospecifically α-13C-Labeled Porphyrins for Studies of Ground-State Hole Transfer in Multiporphyrin Arrays

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Regiospecifically α-¹³C-Labeled Porphyrins for Studies of Ground-State Hole Transfer in Multiporphyrin Arrays