The two positionally isomeric cyclohexanotetraoxacyclotridecanes (13-crown-4 ethers) were synthesized and studied via low-temperature NMR methods. For the 1,4,8,11-tetraoxa isomer, the cyclohexane ring inversion is a degenerate process, whereas for the 1,4,7,11-tetraoxa isomer, a preference of 1.4 k
1H and 13C NMR of substituted dibenzo-14-crown-4 ethers
โ Scribed by Zhihong Chen; Richard A. Sachleben
- Publisher
- John Wiley and Sons
- Year
- 1994
- Tongue
- English
- Weight
- 284 KB
- Volume
- 32
- Category
- Article
- ISSN
- 0749-1581
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โฆ Synopsis
Abstract
Dibenzoโ14โcrownโ4 and eight substituted dibenzoโ14โcrownโ4โethers were studied by 1D and 2D ^1^H and ^13^C NMR and their chemical shifts are reported.
๐ SIMILAR VOLUMES
a See footnote d in Table 1. 'H and "C NMR Spectra of 4 4 - ## Substituted Chalcones KIKUKO HAYAMIZU (to whom correspondence should be addressed), MASARU YANAGISAWA, TETSUKO ISHII,
## Abstract A new type of crown ethers containing a diphenyl ether unit has been prepared, the ring size ranging from 12 to 36. ^1^H and ^13^C NMR spectra of both free ligands and their metalโion complexes have been recorded. For 18โ and 21โmembered compounds a general downfield shift was observed
A series of 14 3-substituted 4-oxoquinolones with or without a substituent (methyl, ethyl) in position 1 were prepared. Literature and measured data were used to study the inรuence of the substituent on the shifts of carbon atoms of these compounds, which are model compounds for antibacterial drugs
The 'H and I3C NMR spectra of a series of structurally related crown ethers have been recorded, and the signals assigned by means of 'H/I3C heteronuclear correlated and 'H/'H homonuclear NOE difference spectroscopy. The NMR parameters so extracted have been used to discuss the preferred, rapidly int