Synthesis 2005(7): 1157-1163  
DOI: 10.1055/s-2005-861861
PAPER
© Georg Thieme Verlag Stuttgart · New York

Fluorination of Betulinines and Other Triterpenoids with DAST

David Biedermanna, Jan Sarek*a, Jiri Klinota, Marian Hajduchb, Petr Dzubakb
a Department of Organic and Nuclear Chemistry, Faculty of Science, Charles University in Prague, Hlavova 8, 128 43 Prague 2, Czech Republic
Fax: +42(22)1951332; e-Mail: jan.sarek@volny.cz;
b Laboratory of Experimental Medicine, Department of Pediatrics, Faculty of Medicine, Palacky University in Olomouc, Puskinova 6, 775 20 Olomouc, Czech Republic
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Publikationsverlauf

Received 1 September 2004
Publikationsdatum:
10. März 2005 (online)

Abstract

Betulinines are lupane, des-E-lupane, 18-lupene, 20(29)-lupene and 18α-oleanane derivatives with antitumor activity. We examined fluorination of these derivatives using diethylaminosulfur trifluoride (DAST) as fluorinating agent. We prepared 19β,28-epoxy-2,2-difluoro-18α-oleanan-3-one (3c), 19β,28-epoxy-2,2-di­fluoro-18α-oleanan-3β-ol (4a), methyl 3β-acetoxy-30-fluorolup-20(29)-ene-28-oate (6b), 3β,28-diacetoxy-22-oxo-21,21-difluorolup-18-ene (8b) and several other fluorinated betulinines for in vitro cytotoxicity tests which failed to demonstrate significant anticancer activity so far.