Our prior study (1) of the roots from Asclepias amplexicaulis Sm (Asclepiadaceae) resulted in the isolation and identification of amplexoside A (1), which had shown cell growth inhibitory activity against the NCI KB cell line from a human nasopharnyx carcinoma (2) . In this report, we wish to present tentative structures for two additional glycosides from this plant, namely, amplexoside B (2) and amplexoside C (3) , which were found to have KB cell line ED50 values (2) of 3.9 and 0.14, re-

No abstract

Thallium perchlorate oxidation of 17P-acetoxy-1 -hydroxy-4-methylestra-l,3,5(1O)-triene (1 ) was used to prepare the steroidal quinol, 17~-acetoxy-4~-hydroxy-4-methylestra-2,5(1O)-dien-l -one (2). which could be isolated as a pair of diastereoisomers. Thallium nitrate in methanol yielded the corresponding 4-methoxy-quinol (3). Treatment of the quinol with HBr or HCI rearranged it to the 1,17~-diacetoxy-3-halogeno-4-methylestra-1,3,5(10)-trienes (4) and (5) (after acetylation) while HI expelled the 4-hydroxy-moiety and reduced it to 1,17Pdiacetoxy-4-rnethylestra-l,3,5(1O)-triene (6). Hydrogen fluoride failed to effect any reaction. Dienone-phenol type rearrangement, whereby the 4-methyl group migrated to C-3 affording 1,4,17P-triacetoxy-3-methylestra-1,3,5(1O)-triene (1 5), was accomplished with BF,-ether and subsequent acetylation. llse of ZnC1,-acetic anhydride was found, on the other hand, to bring about migration of the oxygen moiety and give 1,3,17P-triacetoxy-4-methylestra-l,3,5(1O)-triene (1 2). Attempts to rearrange the 4-methoxy-quinol ether (3) by the above methods failed.

Tl(ClO4)3‐Oxidation des Östratrienols (I) gibt das Chinol (II) (Diastereomerenpaar), dessen Behandlung mit HCl bzw. HBr und anschließender Acetylierung der intermediär gebildeten 1‐Hydroxy‐östratriene zu den 3‐Halogen‐1‐acetoxy‐Derivaten (IIIa) bzw. (IIIb) führt.