1H-NMR Study of Some Substituted Acetophenones and Aryl Methyl Sulphoxides Evidence for Steric Enhancement of Resonance
| Main Authors: | K. GANAPATHY, M. RAMANUJAM |
|---|---|
| Format: | Article Journal |
| Bahasa: | eng |
| Terbitan: |
, 1983
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| Subjects: | |
| Online Access: |
https://zenodo.org/record/6343849 |
Daftar Isi:
- Department of Chemistry, Annamalai University, Annamalainagar-608 002 Manuscript received 19 June 1982, revised 17 May 1983, accepted 1 September 1983 From the proton magnetic resonance chemical shift of the ω-methyl groups of certain substituted acetophenones and aryl methyl sulphoxides, evidence for steric enhancement of resonance is furnished. The chemical shift value of ω-methyl groups of 4-methoxyacetophenone, 4-methylthioacetophenone and 4-methoxyphenyl methyl sulphoxide gets shifted upfield due to greater shielding when there is any substituent at 3-position of the phenyl ring. The extent of shielding seems to be proportional to the bulkiness of the group ortho to the methoxy or the methylthio group.