Dioxopyrrolines.XLII. : Mechanism of 7-Epimerization Reaction of 7-Substituted 5-Ethoxycarbonyl-1-phenyl-2-azabicyclo[3.2.0]heptane-3,4-diones
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- SANO Takehiro
- Showa College of Pharmaceutical Sciences
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- HORIGUCHI Yoshie
- Showa College of Pharmaceutical Sciences
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- TANAKA Kazuhiko
- Showa College of Pharmaceutical Sciences
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- ABE Ken-ichi
- Showa College of Pharmaceutical Sciences
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- TSUDA Yoshisuke
- Faculty of Pharmaceutical Sciences, Kanazawa University
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Description
7-Mono- and 7,7-disubstituted 5-ethoxycarbonyl-1-phenyl-2-azabicyclo[3.2.0]heptane-3,4-diones undergo epimerization at C-7 when treated when treated with base. Experiments using the stereospecifically deuterium labeled compound 6 showed that the inversion of stereochemistries at C-6 and C-7 took place simutaneously in this reaction, thus proving that the reaction proceeded through C_1-C_5 bond fission and recyclization. The suggested intermediate 10 with a highly strained seven membered ring would give either the C_7 epimerized product by a fast recombination or irreversibly give the dihydroazatropolones 9 by a trans- to cis- isomerization of the C=N double bond. Kinetic treatments showed that the latter reaction is slower than the former equilibrium reaction.The analogous 7-epimerization reaction observed in the hydride reduction of the 4-oxo group and in the photolysis of the imidate 24 was proved to proceed with a similar mechanism.
Journal
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- Chemical & pharmaceutical bulletin
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Chemical & pharmaceutical bulletin 37 (3), 652-659, 1989-03-25
The Pharmaceutical Society of Japan
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Details 詳細情報について
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- CRID
- 1571417127438553856
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- NII Article ID
- 110003627579
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- NII Book ID
- AA00602100
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- ISSN
- 00092363
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- Text Lang
- en
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- Data Source
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- CiNii Articles