59748-15-1Relevant articles and documents
Total synthesis and structure-activity relationships of caspofungin-like macrocyclic antifungal lipopeptides
Yao, Jianzhong,Liu, Hongming,Zhou, Ting,Chen, Hai,Miao, Zhenyuan,Dong, Guoqiang,Wang, Shengzheng,Sheng, Chunquan,Zhang, Wannian
experimental part, p. 3074 - 3085 (2012/06/01)
The echinocandins represent a well-known class of macrocyclic antifungal lipopeptides that can be used for treatment of invasive fungal infections. Due to their complex chemical structures and synthetic difficulties, the structure-activity relationships (SARs) of them are still limited. A total synthetic approach was developed to synthesize structurally diverse caspofungin-like antifungal cyclic lipopeptides, allowing for systemically investigating their SARs. Most of the designed cyclic lipopeptides showed potent antifungal activities with broad spectrum. In particular, several compounds (e.g., 30a, 30e-h, 31a-d, 32c, and 33a,b) were more active in vitro against Candida albicans or Aspergillus fumigatus than caspofungin. The findings in this work indicated that the 'left' tripeptide segment of cyclic lipopeptide scaffold might be suitable for a hydrophilic structural motif, whereas the 'right' lipotripeptide segment was preferred as a hydrophobic core. The alkoxy-naphthoyl was found to be optimal side chain and alkyl length could affect the SARs of alkoxy-aroyl side chains.
CHARACTERIZATION OF THE HEXATIC B AND CRYSTAL B PHASES BY OPTICAL MICROSCOPY.
Goodby,Pindak
, p. 233 - 247 (2007/10/02)
Recent investigations concerning the structure of the B phase have unearthed a variety of packing arrangements of the molecular layers for this smectic modification. Two general structures have been discovered; one in which the B phase has three-dimensional crystalline order (crystal B), and one that is characterized by short-range in-plane positional ordering of the constituent molecules, and long-range bond orientational order, both within and between the layers (hexatic B). In this present study n-hexyl 4 prime -n-pentyloxybiphenyl-4-carboxylate (650BC) has been synthesized and its smectic phases characterized. Typically, this ester exhibits an A,B,E phase sequence, with the B phase being of the hexatic type. The synthesis, microscopic textures, and miscibility studies are reported here. The results show that while the two types of B phase appear co-miscible by conventional optical methods, in fact X-ray diffraction studies show that a transition occurs between the two phases in certain binary mixtures. Thus, the hexatic B and crystal B modifications are thermodynamically distinct phases.
