A New Alkaloid from the Seeds of Sophora alopecuroides L.

Abstract Alopecurin A, an alkaloid with an unprecedented skeleton, was isolated from the seeds of Sophora alopecuroides L. The absolute configuration and structure of this compound was identified as (3 S ,12 R )‐3‐hydroxy‐1,7‐diazatricyclo[10.4.0.1 3,7 ]heptadecane‐11,16,17‐trione (=(7 S ,15a R )‐decahydro‐7‐hydroxy‐6 H ‐7,11‐methano‐4 H ‐pyrido[1,2‐ a ][1,7]diazacyclododecine‐4,15,16(12 H )‐trione). The structure and absolute configuration was elucidated by spectroscopic methods, mainly HR‐ESI‐TOF‐MS, IR, 1D‐NMR ( 1 H‐ and 13 C‐NMR), 2D‐NMR (COSY, NOESY, HSQC, HMBC), and particularly X‐ray crystal‐diffraction and CD spectral analysis.