2,2,2-Trifluoroethyl butanoate → 17alpha-Hydroxy-21-butanoyloxy-pregna-4,9(11)-diene-3,20-dione

Beteiligte Stoffe

Reaktionsschritte

A mixture of 1 g (2.879 mM) of 17α,21-dihydroxy-pregna-4,9(11)-diene-3,20-dione and 10 ml of trifluoroethyl butanoate in 100 ml of acetone was reacted at 45° C. in the presence of 5 g of Candida cylindracea lipase for 8-10 hours, adding 1 g of lipase at regular time intervals. After completion of the reaction, the lipase was filtered off and the filtrate was concentrated under vacuum, taking up the residue three times with acetone. The semi-solid residue was purified by chromatography on a silica gel column with a dichloromethane/methanol 99:1 mixture. The less polar components were removed, to obtain the richer fraction which was evaporated to yield 0.95 g (2.29 mM) of 17α-hydroxy-21-butanoyloxy-pregna-4,9(11)-diene-3,20-dione.

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