Hypeisoxazole A, a Racemic Pair of Tetrahydroisoxazole-Fused Benzylisoquinoline Alkaloids from and Structural Revision of Hypecoleptopine.

(±)-Hypeisoxazole A (), a racemic pair of rearranged benzylisoquinoline alkaloids possessing an unprecedented diindeno[2,1-c:2',1'-d] isoxazole scaffold, was isolated from the medicinal herb , along with hypecoleptopine (), whose structure is now revised as a novel spiro-benzylisoquinoline alkaloid with a 6/6/5/6/6 skeleton. Their structures were determined by comprehensive spectroscopic and spectrometric analyses, X-ray diffraction, and computational studies. Racemic mixture of and its pure enantiomers modulated neuronal excitability activity.