Hypeisoxazole A, a Racemic Pair of Tetrahydroisoxazole-Fused Benzylisoquinoline Alkaloids from <i>Hypecoum erectum</i> and Structural Revision of Hypecoleptopine

Abstract

(±)-Hypeisoxazole A (1), 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 Hypecoum erectum, along with hypecoleptopine (2), 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 2 and its pure enantiomers modulated neuronal excitability activity.

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