一个新骨架的C_(19)二萜内酯的晶体结构

Crystal Structure of a C_(19) Diterpene with New Carbon Skeleton

本文报道箭叶橐吾内酯(Sagittolactone),分子式:C_(19)H_(24)O_5,M_r=332.4,单斜晶系,空间群P2_1,a=0.7420(1),b=0.8205(1),c=1.3887(1)nm,β=75.71(1)°,V=0.819nm^3,Z=2,D_c=1.347g·cm^(-1),F(000)=356,T=298K.强度数据由CAD_4四圆衍射仪收集,使用MoKa辐射.结构由直接法解出,经块矩阵与全矩阵最小二乘法修正,最终偏离因子R=0.052,R_w=0.068(单位权方式).结构分析表明,此分予是由五个环构成的失碳二萜内酯,分子中间具有笼状结构.

The crystal of sagittolactone, C_(19)H_(24)O_5, which is colorless and transparent, belongs to monoclinic system with space group P2_1. The unit cell paraments are a= 0.7420(1), b=0.8205(1), c=1.3887(1)nm, β=75.71(1)°, V=0.819nm^3, Z=2. A four-circle diffractometer has been used to observe the diffraction intensities. The crystal structure has been determined by direct method and refined by the block-full-matrix least squares methods. The final agreement factors are R=0.052 and R_W = 0.068 (unit way). The result showed that sagittolactone was consisted of five rings and there were two bridged rings in the molecule.