Inclusion steroids

With very few exceptions, the biological activities of synthetic steroids tend to parallel those of the naturally occurring hormones on which they are patterned. Compounds with distant pharmacological activity are, as a rule, quite rare. It is thus intriguing that inclusion of a tertiary amine at the 11 position of a pregnane leads to a compound with activity far removed from its close analogues. The agent in question, minaxalone (47), exhibits anesthetic activity. 

Dynamics in Organic Inclusion Crystals of Steroids and Primary Ammonium Salts 505... 

As is the case with other classes of steroids, inclusion of nitrogen atoms into corticoids has met with only limited pharmacological success. Compounds... 

Deoxycholic acid (DCA) (17) and apoeholic acid (ACA) (18) are typical examples of the bile acid family of materials, but with the unique property of forming inclusion compounds with a wide variety of guest molecules 92). Partly due to the cis ring junction between rings A and B, and partly due to the conformation of the steroidal side chain these compounds present a convex hydrophobic P-face and a concave hydrophilic a-face, as shown for DCA (19), a classical aid to the formation of inclusion compounds 93). 

In contrast, the fluorescence spectra of the parent y-cyclodextrins (compounds y-CD1, y-CD2, y-CD3, y-CD4) exhibit both monomer and excimer bands in the absence of guests because the cavity is large enough to accommodate both fluorophores (Figure 10.38). The ratio of excimer and monomer bands changes upon guest inclusion. The ratio of the intensities of the monomer and excimer bands was used for detecting various cyclic alcohols and steroids (cyclohexanol, cyclo-dodecanol, i-borneol, 1-adamantanecarboxylic acid, cholic acid, deoxycholic acid and parent molecules, etc.). 

An alternative route to such 6-(l-hydroxyalkyl)-substituted pteridines including 106 is from 2,4,5-triamino-6-butoxypyrimidine 107 and 2-formyloxiranes 108 in which the stereochemical properties are emphasized by the inclusion of the 17-steroidal ester <1992S303>. L-Biopterin 106 was synthesized from the oxirane 108 and 107 via a 5,6-dihydropteridine intermediate which was oxidized in situ to afford the product (Scheme 21). Syntheses of oxiranes and the condensation mechanism in the context of molecular orbital calculations were discussed. The field has been reviewed <1998H(48)1255>. 

CONTENTS Preface. George W. Gokel. Cryptophanes Receptors for Tetrahedral Molecules, Andre Collett, Jean-Pierre Dutasta and Benedict Lozach. Inclusion Polymerization in Steroidal Canal Complexes, Kiichi Takemoto, Mikiji Miyata. Functionalized Tetraazamacrocycles Ligands with Many Aspects, Thomas A. Kaden. Calixarenes as the Third Supramolecular Host, Seiji Shinkai, Kyushu University, Japan. Fluorescent Chemosensors for Metal and Non-Metal Ions in Aqueous Solutions Based on the Chief Paradigm, Anthony W. Czamik. Index. 

Cyclophanes and Steroids That May Form Inclusion Complexes... 

Kurozumi, M., Nambu, N., and Nagai, T. 1975. Inclusion compounds of non-steroidal antiin ammatory and other slightly water soluble drugs with andp-cyclodextrins in powdered fornChem. Pharm. Bull. 

In addition, dietary supplements that have steroidal properties can be purchased legally common ones are dehydroeiandrosteroine (DHEA) and androstenedione. As of 2002, the effects of these dietary supplements are being researched for possible inclusion as an banned substance. 

Several prominent types of host molecule, such as the steroidal bile acids and the cyclodextrins, are chiral natural products that are available as pure enantiomers. Chemical modification of these parent compounds provides an easy route to the preparation of large numbers of further homochiral substances. Since all these materials are present as one pure enantiomer, it automatically follows that their crystalline inclusion compounds must have chiral lattice structures. It is not currently possible to investigate racemic versions of these compounds, but the examples discussed previously in this chapter indicate that very different behaviour could result. 

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. 

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