Autor:	A.P. Kaplun, V. I. Shvets, E L Surkova, A. V. Symon, N. K. Vlasenkova, G. K. Gerasimova, E F Litvin, L M Kozlova, Le Bang Shon
Rok vydání:	2003
Předmět:	chemistry.chemical_classification Betulin Double bond Stereochemistry Organic Chemistry Stereoisomerism Biochemistry Raney nickel Terpene chemistry.chemical_compound chemistry Betulinic acid Epimer Stereoselectivity
Zdroj:	Russian Journal of Bioorganic Chemistry. 29:185-189
ISSN:	1068-1620
DOI:	10.1023/a:1023220701797
Popis:	Two methods of obtaining of 3 alpha-betulinic acid and related compounds from their 3 beta-epimers were studied: the reaction of bimolecular substitution and the stereoselective reduction of 3-ketoderivatives. The substitution of acyloxy by formyloxy group in 3-O-tosyllupeol or of the betulin hydroxyl by benzoyloxy group resulted only in delta 2, 3-elimination products, with none of the expected products of bimolecular substitution being found. The catalytic hydrogenation of betulonic acid over Raney nickel resulted only in reduction of the isopropenyl double bond, whereas the use of 5% Ru/C gave a 60:40 mixture of epimers of dihydrobetulinic acid. Practically the same mixture of betulinic acid epimers was obtained when reducing betulonic acid with L-Selectride. The cytotoxic activity of 3 alpha-betulinic acid increased toward melanoma Bro cells and decreased toward melanoma MS cells.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::e91e1eea81b3cfb5bd024c8aa1311865 https://doi.org/10.1023/a:1023220701797 Zobrazit plný text záznamu Full text from SpringerLink