BOP-mediated one-pot synthesis of C5-symmetric macrocyclic pyridone pentamers

“…Surprisingly, these shape‐persistent Schiff‐base macrocycles are formed exclusively with five‐fold symmetry when 2‐nitro‐6‐formylphenols are used as precursors. Macrocycles with five‐fold symmetry are relatively rare, but include some beautiful examples reported by Flood, Zeng, Moore, Gong, and others . Also, there are other examples where macrocycles with five‐fold symmetry have been prepared in a lengthy, stepwise procedure, or were obtained as a minor byproduct …”

Section: Resultsmentioning

confidence: 99%

The Rich Tautomeric Behavior of Campestarenes

Chen

Guieu

White

et al. 2016

Chemistry A European J

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Campestarenes are a new family of Schiff-base macrocycles that form selectively in a one-step synthesis. These macrocycles with five-fold symmetry show solvent-dependent tautomerization and dimerization or aggregation. In this paper, we have prepared new soluble campestarenes that do not aggregate. The initial single-crystal X-ray diffraction study of a campestarene reveals that these macrocycles are nearly flat. The tautomeric behavior of the campestarenes has been extensively studied by variable-temperature, multinuclear NMR spectroscopy, UV/Vis spectroscopy, and IR spectroscopy. In polar solvents, such as DMF, the molecules exist predominantly in their keto-enamine form, but the enol-imine tautomer is dominant in non-polar solvents. A detailed computational study of the tautomeric forms of campestarenes provides a theoretical basis for their behavior and corroborates the experimental data. The results of this study give the first comprehensive understanding of the electronic and spectroscopic properties of these pentagonal macrocycles.

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“…Recently, we described one unique class of macrocyclic cation‐binding pyridone pentamers ( 1 and 2 , Figure 1a), which are structurally rigidified by a high‐strength intramolecular H‐bonding network [34–39] . This high rigidity in backbone convergently aligns five carbonyl O‐atoms to enclose a small cavity of 2.85 Å in diameter after subtracting the van der Waals radius of O‐atoms (1.52 Å).…”

Section: Figurementioning

confidence: 99%

Macrocyclic Pyridone Pentamers for Highly Selective High‐Capacity Removal of Caesium Ions from Radioactive High‐Salinity Waste

Jiang

Yuan

et al. 2020

Chemistry An Asian Journal

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We report here that macrocyclic H‐bonded pyridone pentamers, containing five properly and convergently spaced electron‐rich O‐atoms that decorate a rigid cavity of 2.85 Å across, exhibit an extraordinarily high yet pH‐independent capacity and selectivity in Cs+ removal. In particular, with [host]=240 μM and [Cs+]=15 μM, a single extraction efficiently removes more than 91% of Cs+ ions from artificial sea water, containing various competitive metal ions at a total concentration of 0.68 M ([total Mn+]/[Cs+]=4.5×104]). To our best knowledge, these pyridone pentamers represent the best small organic molecule‐based extractants that target Cs+ ions.

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BOP-mediated one-pot synthesis of C5-symmetric macrocyclic pyridone pentamers

Abstract: We report here, for the first time, the BOP-mediated one-pot macrocyclization that is facilitated and guided by internally placed intramolecular H-bonds to allow for the highly selective formation of five-residue cation-binding macrocycles.

Cited by 48 publications

References 38 publications

Macrocyclization Reactions: The Importance of Conformational, Configurational, and Template-Induced Preorganization

Macrocyclization Reactions: The Importance of Conformational, Configurational, and Template-Induced Preorganization

The Rich Tautomeric Behavior of Campestarenes

Macrocyclic Pyridone Pentamers for Highly Selective High‐Capacity Removal of Caesium Ions from Radioactive High‐Salinity Waste

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