Jin H L, Stalcup A, Armstrong D W
Department of Chemistry, University of Missouri-Rolla 65401.
Chirality. 1989;1(2):137-41. doi: 10.1002/chir.530010207.
Optical enrichment from racemic dansyl-leucine, dansyl-norleucine, and dansyl-phenylalanine with both beta- and gamma-cyclodextrins in water is reported. Initial crystallization yielded the dansyl-L-Leucine isomer complexed in excess with beta-cyclodextrin with an optical purity of 62-78% depending on experimental conditions. The optical purities obtained for L-norleucine and L-phenylalanine were 71 and 64%, respectively. The optical purity can be increased with continued recrystallization. The dansyl-D-leucine isomer was obtained in the mother liquor with an optical purity of 54-93% depending on experimental conditions. The optical purities obtained for D-norleucine and D-phenylalanine were 72 and 58%. The optical purity of the isomer depended on the molar ratio of host:guest and the pH value of the solution. Optimum enrichment of both enantiomers was achieved with host:guest ratios of 2:1 and 3:1. Although maximum crystalline yield of the dansyl-leucine/CD inclusion complex was obtained at a pH of 3.5, optical purity of both enantiomers was less than that obtained at other pHs. The influence of the molar ratio of host:guest and the pH value of the solution are discussed. This method is suitable for large-scale enantiomeric separations.
报道了在水中利用β-环糊精和γ-环糊精从外消旋丹磺酰亮氨酸、丹磺酰正亮氨酸和丹磺酰苯丙氨酸中进行光学富集。初始结晶得到丹磺酰-L-亮氨酸异构体与β-环糊精过量络合，根据实验条件，其光学纯度为62 - 78%。L-正亮氨酸和L-苯丙氨酸的光学纯度分别为71%和64%。通过持续重结晶可提高光学纯度。丹磺酰-D-亮氨酸异构体在母液中获得，根据实验条件，其光学纯度为54 - 93%。D-正亮氨酸和D-苯丙氨酸的光学纯度分别为72%和58%。异构体的光学纯度取决于主体与客体的摩尔比以及溶液的pH值。主体与客体比例为2:1和3:1时，两种对映体均实现了最佳富集。虽然丹磺酰亮氨酸/环糊精包合物的最大结晶产率在pH为3.5时获得，但两种对映体的光学纯度均低于在其他pH值下获得的纯度。讨论了主体与客体摩尔比和溶液pH值的影响。该方法适用于大规模对映体分离。
