【摘要】 我们从菊科莶属植物腺梗莶SiegesbeckiaPubescensMakino的地上部分分离到一个新的天然产物17－isobuthyloxy-18-hydroxy－kauran－19－cioacid．本文主要报道用1H－1HCOSY，13C－1HCOSY，NOESY，HMBC，HMQC等技术确定其结构并归属其质子和碳的化学位移．同时用NOESY确定其相对构型．用HMBC确定酰基碳与隔氧相连的碳原子上的氢相关，从而确定酰基的连接位直，也可用于解决其它基团的准确连接位置．更多还原

【Abstract】 A New Kauran compound was isolated from the herbs of Siegesbeckia pubascens, named as 17 -isobuthyloxy - 18 -hydroxy-kauran - 19 - oic acid, all the 1H and 13C NMR chemical shifts of the com-pound were assigned by 1H - 1H COSY, 13C - 1H COSY, NOESY, HMBC, 2D NMR techniques. Its relative configuration is discussed by NOESY, The connection position of acyl radical in the structure was assigned by HMBC.更多还原