Mayer S C, Carroll P J, Joullié M M
Department of Chemistry, University of Pennsylvania, Philadelphia 19104-6323, USA.
Acta Crystallogr C. 1995 Aug 15;51 ( Pt 8):1609-14. doi: 10.1107/s0108270194013405.
An X-ray crystal analysis of phi-lactone N-¿1-¿N-¿4-¿[3- hydroxy-5-methyl-1-oxo-4-(N-L-threonylamino)heptyl]- oxy¿-2,5-dimethyl-1,3-dioxohexyl¿-L-leucyl¿-L-prolyl¿- N,O-dimethyl-L-tyrosine hydrobromide hydrate (1a), C42H66N5O11+.Br-.H2O, was obtained in order to determine the backbone folding of the macrocycle and to compare the results obtained with those reported previously for the natural product didemnin B (1b). Some differences were noted in the torsion angles of the two conformers of the hydrobromide salt, denoted (1a) and (1a'). The conformation of (1a') resembled the conformation of (1b) more closely than did that of (1a). Certain regions of both crystal backbones were more flexible than those in didemnin B; however, the transannular hydrogen bonds in both (1a) and (1a') were somewhat stronger than in (1b).
对 φ-内酯 N-｛1-｝-N-｛4-｝-[3-羟基-5-甲基-1-氧代-4-(N-L-苏氨酰氨基)庚基]-氧基｝-2,5-二甲基-1,3-二氧己基｝-L-亮氨酰｝-L-脯氨酰｝-N,O-二甲基-L-酪氨酸氢溴酸盐一水合物（1a），即 C42H66N5O11⁺·Br⁻·H2O，进行了 X 射线晶体分析，以确定大环的主链折叠方式，并将所得结果与先前报道的天然产物双溴马啉 B（1b）的结果进行比较。在氢溴酸盐的两种构象体（分别记为（1a）和（1a'））的扭转角上发现了一些差异。（1a'）的构象比（1a）的构象更类似于（1b）的构象。两种晶体主链的某些区域比双溴马啉 B 中的区域更具柔性；然而，（1a）和（（1a'）中的跨环氢键比（1b）中的氢键略强。
