Synthesis, alkali metal picrate extraction, and alkali metal cation binding selectivities of some new cage‐annulated polyoxamacrocyclic crown ethers

Marchand, Alan P.; Huang, Zhi‐Zhen; Chen, Zhibing; Hariprakasha, H. K.; Namboothiri, Irishi N. N.; Brodbelt, Jennifer S.; Reyzer, Michelle L.

doi:10.1002/jhet.5570380618

Cited by 21 publications

(14 citation statements)

References 27 publications

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“…All 1 H, 13 C and 2D NMR spectra were recorded on a Varian Unity Inova-400 MHz spectrometer using approximately 50 mg of sample per 0.5 mL of solvent.…”

Section: Methodsmentioning

confidence: 99%

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NMR elucidation of some pentacycloundecane derived ligands

et al. 2007

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The complete NMR elucidation of four pentacycloundecane (PCU) derived ligands is reported. 2D NMR techniques are used to overcome the problem of major overlapping of methine signals on the cage skeleton. One of the cage ligands is chiral and the 13 C NMR signals of the leucinol side ''arms'' to the cage appear to be split into two or more peaks indicating either impurities or conformational differences. Impurities were ruled out and the only logical explanation for this unusual observation appears to be conformational effects due to different positions of the two relative bulky side chains or ''arms''. The rigid cage skeleton is known for through space deshielding of signals in close proximity to oxygen atoms attached to the cage skeleton. The leucinol side chains in closer proximity to the cage ether bridge would experience a larger shielding effect causing those carbon atoms to be shifted upfield with respect to the corresponding atoms in other conformations. The intrinsic chiral nature of the cage could also play a role in this case to perhaps enhance the observed effect.

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“…All 1 H, 13 C and 2D NMR spectra were recorded on a Varian Unity Inova-400 MHz spectrometer using approximately 50 mg of sample per 0.5 mL of solvent.…”

Section: Methodsmentioning

confidence: 99%

“…Treatment of the dione 5 with excess Grignard reagent (allyl magnesiumbromide) yields the alkene diol 6. Dehydration of the diol under Dean-Stark conditions produced the diene derivative 7 [10,13,14]. These reactions are outlined in Scheme 1.…”

Section: Introductionmentioning

confidence: 99%

NMR elucidation of some pentacycloundecane derived ligands

et al. 2007

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“…The synthesis of the endo-endo cage diol 2 is described by Marchand et al 11 and Govender et al 10 When the ratio of Grignard reagent to dione is limited to 1 : 1, the cyclic ether 5 is formed and may be recrystallized from an ethyl acetate-n-hexane (3 : 2) mixture. The NMR data of 5 are summarized in Tables 1 and 2.…”

Section: Synthesis Of the Pcu Cyclic Ether (5) 18mentioning

confidence: 99%

“…1). The endo-endo diol 2 10,11 is an intermediate for the diol 4, 12,13 which is used in various crown ethers 11,14 -16 and macrocycles. 10,17 The diene diol 2 is normally synthesized with excess Grignard reagent.…”

Section: Introductionmentioning

confidence: 99%

NMR assignments of a di‐pentacyclo‐undecane cyclic ether

Kruger

Ramdhani

2006

Magnetic Reson in Chemistry

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The X-ray structure of a di-pentacyclo-undecane cyclic ether was recently reported. As part of a programme to use NMR spectroscopy for the structure elucidation of cage compounds, the complete NMR assignments of the cyclic ether was attempted. Major overlap of proton and carbon signals of the two cages is observed. It was required to elucidate the fragment analogues that represent similar structural features of the cyclic ether in order to get an approximate but reasonable insight into the complex overlapping signals. Normal 2D NMR techniques were utilized to assign the various NMR signals.

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“…[15,16] This diene 7 is an intermediate in the synthesis of all the derivatives 1-5 being investigated. Ozonolysis of 7 followed by an oxidative workup using formic acid and hydrogen peroxide afforded the PCU diacid 8.…”

Section: Introductionmentioning

confidence: 99%

NMR elucidation of a novel (S)‐pentacyclo‐undecane bis‐(4‐phenyloxazoline) ligand and related derivatives

Boyle

Govender

Kruger

et al. 2008

Magnetic Reson in Chemistry

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The NMR elucidation of a novel ligand (S)-pentacyclo-undecane bis-(4-phenyloxazoline) and related pentacyclo-undecane (PCU) derivatives is reported. Two-dimensional NMR proved to be a powerful technique in overcoming the difficulties associated with the elucidation of these compounds when only one-dimensional NMR data is utilized. A chiral substituent was introduced to both 'arms' of the PCU skeleton to produce derivatives 1-3. These derivatives display C(1) symmetry with all thecage atoms being nonequivalent. Owing to overlapping of peaks in the (1)H spectra, identification of these diastereomeric protons was very difficult. The (13)C spectra gave rise to clear splitting of the nonequivalent carbons. This is unusual compared to similar PCU derivatives with chiral substituents as splitting of all the diastereomeric cage carbons has not yet been reported. Nuclear Overhauser enhancement spectroscopy (NOESY) correlations of derivatives 1-3 confirm the different conformations of the molecule in which the side 'arms' occupy different orientations with respect to cage moiety.

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Synthesis, alkali metal picrate extraction, and alkali metal cation binding selectivities of some new cage‐annulated polyoxamacrocyclic crown ethers

Cited by 21 publications

References 27 publications

NMR elucidation of some pentacycloundecane derived ligands

NMR elucidation of some pentacycloundecane derived ligands

NMR assignments of a di‐pentacyclo‐undecane cyclic ether

NMR elucidation of a novel (S)‐pentacyclo‐undecane bis‐(4‐phenyloxazoline) ligand and related derivatives

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