Rhaponticin and its 3”-fluoroanalog have been prepared from easily accessible starting materials. The key step of these syntheses is the silver carbonate-mediated glycosidation reaction employed for the selective formation of a β -glycosidic bond. A palladium acetate-catalyzed Heck-Mizoroki reaction in triethanolamine established an (E) configuration in the stilbene with simultaneous deprotection of the carbohydrate.
A novel class of nucleoside analogues containing adenine, hypoxanthine, thymine, uracil, thiouracil and cytosine as the heterocyclic moieties have been prepared starting from 2-phenylcyclopropylamine. These compounds showed weak antitumor activity. The resolution of the racemates on an analytical scale was performed by HPLC using chiral phases.
Several hydrolytic enzymes (porcine liver esterase, lipase from wheat germ type I, and the lipase from rhizopus javanicus) efficiently deacetylate laevoglucosane triacetate (2) with good regioselectivity into diacetylated laevoglucosane derivatives (3-5).
Starting from a suitable protected (fluorocyclopropyl)methanol derivative a novel class of cyclopropanoid monofluorinated nucleoside analogues can be accessed very conveniently by a short sequence of steps.
A novel class of trans-configurated difluorinated cyclopropanoic nucleoside analogues containing a methylene spacer between the cyclopropane ring and the heterocycle has been prepared. Some of these compounds showed weak anti-HIV activity in preliminary screenings.
Starting from (2,2-difluorocyclopropyl)methanol a novel class of difluorinated cyclopropanoid nucleoside analogues containing two hydroxymethyl side chains was synthesized in a straightforward way. Several of the final compounds could be obtained in an enantiomerically pure form by HPLC using chiral stationary phases.
A convenient synthesis has been developed for the synthesis of cyclopropanoid nucleoside analogues that possess no additional spacer groups between the heterocycle and the hydroxylated cyclopropane ring. For some of these compounds the respective enantiomers could be separated on an analytical scale by means of HPLC using chiral phases.