title: Synthesis of 28a-homoselenolupanes and 28a-homoselenolupane saponins.
abstract: A practical synthesis of 28a-homo-28a-selenolupane triterpenes and the corresponding selenosaponins containing d-mannose, l-arabinose, l-rhamnose, and d-idose moieties is described. Selenium containing triterpenes were obtained from the readily available 3-O-allyl-homobetulin mesylate by nucleophilic substitution with the selenocyanate ion which upon reduction of the -SeCN group afforded the free selenol. Glycosylation using classical Schmidt donors gave 1,2-trans selenosaponins as the main product as well as minute amounts of 1,2-cis isomers. This is one of the very few examples of the synthesis of selenoglycosides by direct glycosylation of free selenols. The studied selenol showed high resistance to air oxidation resulting in good stability during the synthesis of selenolupane derivatives. Cytotoxic activities of new homoselenolupane derivatives were also evaluated in vitro and revealed that some triterpenes exhibited an interesting profile against human cancer cell lines.
authors.affiliation: Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland. zbigniew.pakulski@icho.edu.pl and Pharmaceutical Research Institute, Rydygiera 8, 01-793 Warsaw, Poland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Sidoryk
authors.affiliation: Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Palacký University, Šlechtitelů 27, 783 71 Olomouc, Czech Republic.
authors.forename: Lucie
authors.initials: L
authors.lastname: Rárová
authors.affiliation: Laboratory of Growth Regulators, Centre of the Region Haná for Biotechnological and Agricultural Research, Institute of Experimental Botany ASCR & Palacký University, Šlechtitelů 27, 783 71 Olomouc, Czech Republic. miroslav.strnad@upol.cz.
authors.forename: Jana
authors.initials: J
authors.lastname: Oklešťková
authors.affiliation: Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland. zbigniew.pakulski@icho.edu.pl.
authors.forename: Zbigniew
authors.initials: Z
authors.lastname: Pakulski
authors.affiliation: Laboratory of Growth Regulators, Centre of the Region Haná for Biotechnological and Agricultural Research, Institute of Experimental Botany ASCR & Palacký University, Šlechtitelů 27, 783 71 Olomouc, Czech Republic. miroslav.strnad@upol.cz.
authors.forename: Miroslav
authors.initials: M
authors.lastname: Strnad
authors.affiliation: Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland. zbigniew.pakulski@icho.edu.pl.
authors.forename: Piotr
authors.initials: P
authors.lastname: Cmoch
authors.affiliation: Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland.
authors.forename: Roman
authors.initials: R
authors.lastname: Luboradzki
mesh_terms: D000970:Antineoplastic Agents / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*; D045744:Cell Line, Tumor; D060326:Chemistry Techniques, Synthetic; D006801:Humans; D012503:Saponins / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*; D012643:Selenium / Q000737:chemistry*; D014315:Triterpenes / Q000737:chemistry*; D053978:Pentacyclic Triterpenes
chemical_list: D000970:Antineoplastic Agents; D012503:Saponins; D012643:Selenium; D014315:Triterpenes; C480546:lupane; D053978:Pentacyclic Triterpenes