Abrahamsson S, Dahlén B
Chem Phys Lipids. 1977 Sep;20(1):43-56. doi: 10.1016/0009-3084(77)90054-8.
Crystals of cholesteryl-17-bromoheptadecanoate (C44H77BrO2) are monoclinic (P21) with a = 7.663(2), b = 10.311(5), c = 55.96(2) A and beta = 103.10(3 degrees). These are two molecules in the asymmetric unit which have different conformations of the cholesterol side chain and about the ester bond. The molecules pack with regions of only steroid skeleta alternating with regions of hydrocarbon chains. Due to the packing requirements of the skeleta the carbon chains are forced into a hybrid type packing which contains features of the earlier known O perpendicular and T parallel subcells. The subcell (HS1) is orthorhombic with as = 10.3, bs = 7.5 and cs = 2.54 A. The molecular packing is such that the omega-bromine atoms do not continue the trans-carbon chains but adopt a gauche conformation.
胆甾醇-17-溴十七烷酸酯（C44H77BrO2）晶体为单斜晶系（P21），a = 7.663(2)，b = 10.311(5)，c = 55.96(2) Å，β = 103.10(3°)。不对称单元中有两个分子，其胆固醇侧链和酯键的构象不同。分子堆积时，仅甾体骨架区域与烃链区域交替排列。由于骨架的堆积要求，碳链被迫形成一种混合类型的堆积，其中包含早期已知的O垂直和T平行亚晶胞的特征。亚晶胞（HS1）为正交晶系，as = 10.3，bs = 7.5，cs = 2.54 Å。分子堆积使得ω-溴原子不延续反式碳链，而是采取gauche构象。
