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Indian Journal of Chemistry -Section B (IJC-B) >
IJC-B Vol.45B [2006] >
IJC-B Vol.45B(07) [July 2006] >
| Title: | Protonation effect on chemical shifts of some piperidones — unusual influence by anions |
| Authors: | Manimekalai, A
Jayabharathi, J |
| Keywords: | NMR data
picrates
anion influence |
| Issue Date: | Jul-2006 |
| Publisher: | CSIR |
| IPC Code: | Int.Cl.8 C07D |
| Abstract: | 1H and 13C NMR spectra are recorded for twelve picrate
derivatives 4-15 derived from some 3-alkyl-2,6-diarylpiperidin-4-ones
and 3,5-dimethyl-2,6-diarylpiperidin-4-ones. The difference in the chemical
shift of equatorial methylene proton and axial methylene proton at C(5) [ =  eq - ax] is highly negative in 4-13
which is in contrast to the value observed in the corresponding parent
piperidin-4-ones and this is attributed to the syn 1,3-diaxial
interaction between the axial N-H bond and axial hydrogen at C-5. The effect of
protonation on the chemical shifts was studied in detail. The chemical shifts
of the heterocyclic ring protons are influenced by the picrate anion. |
| Page(s): | 1686-1691 |
| ISSN: | 0975-0983(Online); 0376-4699(Print) |
| Source: | IJC-B Vol.45B(07) [July 2006]
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