The 17O, 13C and 1H NMR spectra of a number of 1,2-dialkoxyethenes R1OCHxCHOR2 were recorded. The O atoms, in particular those of the E forms, are strongly shielded relative to the 17O nuclei of the corresponding alkyl vinyl ethers Moreover, in compounds of the type ROCHxCHOMe, the di β er-ROCHxCH 2
13C and 17O NMR spectra of ketenes: A new and unusual type of heavy-atom effect
β Scribed by H. Duddeck; H.-W. Praas
- Publisher
- John Wiley and Sons
- Year
- 1993
- Tongue
- English
- Weight
- 233 KB
- Volume
- 31
- Category
- Article
- ISSN
- 0749-1581
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β¦ Synopsis
Abstract
The ^13^C and ^17^O chemical shifts of a number of ketenes are reported and discussed in terms of electronic and mesomeric substituent influences. New deshielding Ξ±β and shielding Ξ³βheavyβatom effects are reported. The corresponding data for carboxylic acid bromides and chlorides are given.
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Carbon, nitrogen and oxygen NMR spectra of some nitro derivatives of pyrrole and imidazole have been investigated. The 13C chemical shifts of para-carbons and the 170 chemical shifts of the nitro group correlate qualitatively with the electron densities on these carbon and oxygen atoms, which in tur
## Abstract ^1^H and ^13^C nmr spectra of several __N__β and Cβsubstituted carbazoles (Series 1, 2, 3 and 4) were measured. Correlations between chemical shifts and substituent constants show that these parameters describe properly the substituent effect on the nmr phenomena. Atomic charge densitie
The 1H and 13C NMR spectra of 4-substituted phenylthiol acetates, benzoates and cinnamates and the 17O NMR spectra of a few thiol acetates were measured. The 13C chemical shifts of C-1 of the thiol esters when correlated with appropriate substituent-induced chemical shifts (SCS) of monosubstituted b
The 1H, 13C and 17O NMR spectra for four series of C-2-substituted enaminones are reported : MeCO(Me)CxCHNHR (1), EtCO(Me)xCHNHR (2), PhCO(Me)CxCHNHR (3) and MeCO(Me)CxCHNHR (4). The 1H, 13C and 17O NMR data for these enaminones show that 1 and 2 exist as mixtures of E-and Z-forms, 3 exists mainly i