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Abstract
The behavior of hydrochlorides and methiodides of several N-substituted 4-piperidones in CH3OH has been studied by 13C nuclear magnetic resonance (NMR) spectroscopy. All the piperidone salts studied were observed to exist as their hemiacetal form at room temperature, in contrast to the case of free piperidones, where an equilibrium mixture of ketone and hemiacetal was obtained. This difference could be accounted for by the effect of the positive charge on nitrogen, which increases the instability of the salt of the keto-form. Acetal formation was observed only in more acidic solutions. The corresponding O- and S-analogs were also examined in CH3OH, and it was found that they are converted readily to the acetals in the presence of trace amounts of acid. The reaction mechanisms of these compounds and piperidone salts are compared and discussed. 13C NMR techniques were found to be useful for studying the equilibrium system containing both hemiacetal and acetal.
Journal
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- Chemical and Pharmaceutical Bulletin
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Chemical and Pharmaceutical Bulletin 28 (12), 3665-3669, 1980
The Pharmaceutical Society of Japan
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Keywords
Details 詳細情報について
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- CRID
- 1390001204167313280
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- NII Article ID
- 110003623895
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- NII Book ID
- AA00602100
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- ISSN
- 13475223
- 00092363
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- Text Lang
- en
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- Data Source
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- JaLC
- Crossref
- CiNii Articles
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- Abstract License Flag
- Disallowed