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Synthesis of triterpenoid-based ring-A azepanone and gem-3-nitro-3chloro-derivatives by ozonolysis of 3-oximino-28-oxoallobetulin under normal and acidic solvolysis conditionsстатья Исследовательская статья
Информация о цитировании статьи получена из
Web of Science,
Scopus
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 13 сентября 2017 г.
- Авторы: Yamansarov Emil Yu, Kazakova Oxana B., Medvedeva Natalya I., Lobov Alexander N., Suponitsky Kyrill Yu
- Журнал: Tetrahedron
- Том: 73
- Номер: 30
- Год издания: 2017
- Издательство: Pergamon Press Ltd.
- Местоположение издательства: United Kingdom
- Первая страница: 4341
- Последняя страница: 4347
- DOI: 10.1016/j.tet.2017.05.094
- Аннотация: It was found that ozonolysis of 3-oximino-28-oxoallobetulin under normal conditions (CHCl3, 0 degrees C) led to the preferred formation of azepanone (lactam) ring-A (61%) and partial removal of oximino-moiety to 28-oxoallobetulone (28%). In the case of ozonation under acidic conditions (5% vol. HCI in CHCl3, 0 degrees C) the attendant formation of minor products of 28-oxoallobetulin was observed, besides lactam (48%), with a total yield of 28%. These were 2,2-dichloroazepanone, (3S)-3-nitro-3-chloro-, 2-cyano-3,4-seco-4(23)en-, 2-cyano-3,4-seco-23-nor-4,28-dioxo-defivatives and also a mixture of A-seco-24-chlorine-contained products. 3-Nitro-3-chloro-28-oxoallobetulone was synthesized for the first time as a single (3S)-diastereoisomer with a yield of 9% in the reaction with ozone, while oxidation of 3-oximino-28oxoallobetulin with oxone in the presence of NaCI and H2O led to the mixture of (3R)-and (3S)-diastereomers. The application of ozone in the oxidative synthesis of ring -A lactams from 3-oximinotriterpenoids seems to be an alternative route to the Beckmann rearrangement.
- Добавил в систему: Ямансаров Эмиль Юлаевич