摘要 : By means of 2D NMR experiments (COSY, HMQC, HMBC, ROESY), the constitution of the photoreaction product 3-deoxo-1 alpha,3 alpha-diacetoxy-1,2,3,3,8,30-hexahydro-18 beta H (2), obtained by photolysis of 7-deacetoxy-7-oxokhivorin (1... 展开 By means of 2D NMR experiments (COSY, HMQC, HMBC, ROESY), the constitution of the photoreaction product 3-deoxo-1 alpha,3 alpha-diacetoxy-1,2,3,3,8,30-hexahydro-18 beta H (2), obtained by photolysis of 7-deacetoxy-7-oxokhivorin (1) in methanol, was shown to be a ring B seco-limonoid with the 14,15-epoxide intact. The configuration of C-8 is R. Ring C adopts a twist-boat conformation. No conformational preferences for the rotation of ring A in 2 with respect to rings C/D and for the side-chain C-6/C-7 could be detected. Nearly all H-1 and all C-13 resonances were assigned unambiguously. (C) 1998 John Wiley & Sons. [References: 20] 收起