Kcaction or rotcncinc ( I a) and arnorphigenin {2a) with hydroxylaminc in alkalinc mcdium affords a mixturc ofthe isoximes 5 and structurcs. slereochemistry. and the mechanisms of formalion of I liese products are discussed. Reaktionen yon Rotenoiden mit Hydroxylamin Die Reakdon yon Rotenon ( l a ) und m,, t3y-Kimc und h, SOwie die neucn Spirovcrhindungen 12a. , , und ,3a, b mit eincr Aminogruppc in 6a-Pasition. Dic Strukiuren. die Stcrcochemie und dic Bildungsmechanismen dicser Prtiduktz wcrdcii disk utiert. 6, and Ihc new 6a-NH: spire dcivatives 12% b and 13a, b. The droxylamin in alkaljschcm ~~d i ~~ liefcrt ejn ~~~; ~~l der [so-
It is known that treatment of rotenoids with hydroxylamine in the presence of sodium acetate affords normal oximes, different from the isoximes prepared in alkaline medium' -4). Earlier investigations'.*' describe the preparation of these carbonyl derivatives and point out the phenolic character and the positive FeCI3 reaction of the latter as the main difference between them.
Later, in 1961, Crombie and co-workers3' studied the reaction of rotenone, Rt-(1 a), with hydroxylamine. On the basis of IR data and a positive FeCI, reaction they suggested the existence of the isoxime of l a as a tautomeric mixture of the isoxazoline 5 and its tautomer. Nagai and his colleagues re-examined the same reaction in the presence of potassium hydroxide. Recently, in 1986, while this investigation was still going on, they reported4) the formation of the isoxime of l a as a single product and offered 'H-NMR data in support of its structure as [l]benzopyrano[4,3-d]isoxazole derivative 5, with a cis junction of the rings B and C. However, no presence of any other reaction product was indicated.
Here, the results from the oximation of Rt-(1 a) and amorphigenin, Amg-(2a), in alkaline medium are presented, using a modification of the procedure described by Butenandt 'I,