The effectofadjacentcarboniumion centers on the chemical shifts ofmethylgroups in the n.m.r. spectrum has been the subject of numerous studies (1,2). However, alkyl shifts in ., systems where partial. carbonic ion character has been Introduced by protonatlon of a carbowl function (e.g. I) have not b
Conformational equilibria of C-methyl groups in piperidines and N-methylpiperidines
β Scribed by Ernest L. Eliel; Duraisamy Kandasamy; William R. Kenan Jr.
- Publisher
- Elsevier Science
- Year
- 1976
- Tongue
- French
- Weight
- 245 KB
- Volume
- 17
- Category
- Article
- ISSN
- 0040-4039
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π SIMILAR VOLUMES
The conformations of the isopropyl groups and the barriers to conformational interconversion in N,N-diisopropylbenzamide (l), and its thio (2) and seleno (3) analogues have been studied by dynamic 'β¬I NMR spectroscopy. In 1 only one conformation is observed, whereas 2 and 3 exist as mixtorc?s of thr
A detailed conformational analysis was performed on the chair forms of piperidine, N-methylpiperidine, and some methylated derivatives Ε½ . using HartreeαFock HF and MP2 ab initio methods with several basis sets Ε½ . from 3α21G to 6α311qqG\*\* , and the most widely used semiempirical Ε½ . approaches MN