Four steroidal alkaloids from the leaves of Buxus sempervirens.
Four new steroidal alkaloids, N20-formylbuxaminol E [(20S)-16alpha-hydroxy-20-(formylamino)-3beta-(dimethylamino)-9,10 -seco-buxa-9(11),10(19)-diene] (1), O16-syringylbuxaminol E [(20S)-16alpha-syringoyl-3beta-(dimethylamino)-20-(amino)-9, 10-seco-buxa-9(11),10(19)-diene] (2), N20-acetylbuxamine G [(20S)-20-(acetylamino)-3beta-(methylamino)-9,10-seco-buxa-9(11),1 0(19)-diene] (3) and N20-acetylbuxamine E [(20S)-20-(acetylamino)-3beta-(dimethylamino)-9,10-seco-buxa-9(11) ,10(19)-diene] (4) were isolated from the leaves of Buxus sempervirens. Their structures were determined mainly on the basis of 2D NMR studies.