The culture broth of Calcarisporium arbuscular afforded 12-deoxyroridin J (1) and 12-deoxyepiisororidin E (2). Their structures were elucidated based on NMR and ECD analyses. Both molecules showed negative ECD splitting at 240 nm and a negative Cotton effect at 200 nm. Density functional theory calculations revealed that the former is caused due to the ECD exciton coupling between the C1′–C3′ enone and C7′–C11′ dienone chromophores, whereas the latter corresponds to the longer wavelength fragment of the negative ECD splitting in the vacuum ultraviolet (VUV) region at 190 nm which cannot be observed with conventional circular dichroism spectrometers. Simultaneous isolation of the regular roridins suggested that 1 and 2 are obtained through the same biosynthetic pathway. Since the 12-epoxy functionality is introduced at an early biosynthetic stage, 1 and 2 are assumed to be derived from reductions of the 12,13-epoxide in the corresponding regular roridins at a later biosynthetic stage.

杯状Calcarisporium的培养液提供了12-脱氧罗丹定J（1）和12-脱氧表皮抑菌素E（2）。根据NMR和ECD分析阐明了它们的结构。两种分子在240 nm处均显示出负ECD分裂，在200 nm时显示出负的Cotton效应。密度泛函理论计算表明，前者是由于C1'–C3'烯酮和C7'–C11'二烯酮生色团之间的ECD激子耦合引起的，而后者则对应于负ECD在真空中分裂的较长波长片段常规圆二色光谱仪无法观察到的190 nm紫外（VUV）区域。同时隔离常规roridins建议1和2通过相同的生物合成途径获得。由于12-环氧官能团是在生物合成的早期阶段引入的，因此1和2假定是从随后的生物合成阶段相应的规则鸟苷中12,13-环氧化合物的还原而来的。