Bile acid derivatives molecular structure

I thank my coworkers, who are mentioned in the references, for the work on bile-acid-derived molecular receptors carried out at Bangalore. Financial support by the Department of Science and Technology and by the Department of Biotechnology is gratefully acknowledged. I also thank Mr Koushik Das Sarma for drawing all the structures for this article. 

CHARACTERISTIC STRUCTURES OF BILE ACID DERIVATIVES 2.1 Unique Molecular Structures... 

We have researched the inclusion abilities of bile acid derivatives by using more than one hundred organic compounds as guest candidates. The inclusion phenomena vary from one case to another, indicating that subtle changes in molecular structures induce alteration in their molecular assemblies. In fact, X-ray diffraction studies prove that the steroidal hosts form various assemblies such as monolayers, bilayers, helical tubes, and so on, as shown in Figure 2. Therefore, systematic investigation of inclusion crystals of bile acid derivatives is expected to reveal a relationship between their molecular structures, assemblies and inclusion behavior. 

Early studies of bile acid mass spectra were made by Bergstrom, Ryhage, and Stenhagen (3-5) and the results were used to determine the structure of Hammarsten s a-phocaecholic acid (6). Other groups applied mass spectrometry to the elucidation of structures of the closely related bile alcohols (7). At about this time combined gas chromatography-mass spectrometry instruments were developed that could be used in studies of compounds with molecular weights as high as those of bile acid derivatives (8-13). The early... 

Maitra, U. Nath, S. Bile acid derived PET-based cation sensors molecular structure dependence of their sensitivity. Chem. Aslan J. 2009,4, 989-997. 

Bile acids can be modified to many derivatives due to their unique molecular structures, as listed in Table 1. First, we can convert the functional groups at the side-chains from carboxylic acid to amide, alcohol, ester, and so on. Second, we can change the length of the side-chains by decreasing or increasing their methylene number. Third, we can regulate the direction of the hydroxyl groups of the skeletons at the axial or equatorial positions. 

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