Low Molecular Mass Gelators of Organic Liquids and the Properties of Their Gels

Improving drug solubility for oral delivery using solid dispersions.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/jps.2600600902

Pharmaceutical Applications of Solid Dispersion Systems

Water gelation by small organic molecules.

In this review, we describe the recent advances in supramolecular helical assemblies formed from chiral and achiral small molecules, oligomers (foldamers), and helical and nonhelical polymers from the viewpoints of their formations with unique chiral phenomena, such as amplification of chirality during the dynamic helically assembled processes, properties, and specific functionalities, some of which have not been observed in or achieved by biological systems. In addition, a brief historical overview of the helical assemblies of small molecules and remarkable progress in the synthesis of single-stranded and multistranded helical foldamers and polymers, their properties, structures, and functions, mainly since 2009, will also be described.

Supramolecular Helical Systems: Helical Assemblies of Small Molecules, Foldamers, and Polymers with Chiral Amplification and Their Functions

Thermally reversible jellies of optically active 12-hydroxyoctadecanoic acid (12HOA) with CCl4 or aromatic solvents form a lyotropic mesophase, which shows enantiomeric circular dichroism (CD) and induced CD due to achiral molecules added to the jellies, indicating that the jellies have a supramolecular helicoidal structure. The X-ray examination revealed that the jellies are composed of a number of small, ordered domains with such a lamellar structure as is observed in the crystalline solid. The supramolecular helicoidal structure was associated with the lamellar structure; as a result, it was suggested that the lyotropic mesophase has a chiral smectic structure and, furthermore, that the mesophase is present in thin, fibrous aggregates of 12HOA molecules within which the jellies are enmeshed.

Chiral Mesophases of 12-Hydroxyoctadecanoic Acid in Jelly and in the Solid State. I. A New Type of Lyotropic Mesophase in Jelly with Organic Solvents

A new method was developed for preparing an aqueous colloidal dispersion ofΒ-carotene. This method consists of preparing a solid mixture ofΒ-carotene and polyvinylpyrrolidone (PVP) from their chloroform solution by evaporating the solvent and dissolving the mixture into water.

A methode for preparing an aqueous colloidal dispersion of organic materials by using water-soluble polymers: Dispersion ofΒ-carotene by polyvinylpyrrolidone

Enantiomorphism in the Helical Aggregate of Lithium 12-Hydroxystearate

It was found, by electron-microscope observation, that D(or L)-12-hydroxystearic acid and its Li soap crystallize from a solution in various solvents in the form of a twisted fiber. The twist was left-handed for the D-acid and right-handed for the L-acid, while the Li soap gave results just opposite to those of the corresponding acid. The DL-acid separated out not fibers, but platelike crystals, and its Li soap produced non-twisted fibers. Thus, an enantiomorphic relationship for the sense of twist between the D-enantiomer and the L-enantiomer was found both for the acid and for the Li soap.

Studies of Helical Aggregates of Molecules. I. Enantiomorphism in the Helical Aggregates of Optically Active 12-Hydroxystearic Acid and Its Lithium Salt

The monolayer properties of chiral and racemic 12-hydroxyoctadecanoic acids (12HOA) have been studied. Both acids showed, in each pressure-area isotherm, a pressure plateau. This was interpreted as a two-dimensional phase transition region: from the expanded monolayer composed of bent chain molecules with both the hydroxyl and carboxyl groups attached to the water surface, to the condensed monolayer composed of straight chain molecules oriented steeply to the water surface. It was suggested by measuring infrared spectra of the collapsed films and the built-up films that the condensed monolayer involves intermolecular hydrogen bonds. Differences between (R)- and dl-12HOA were found in the plateau pressure and its temperature dependence leading to the transition energy. These results were attributed to the formation of a recemic molecular compound during condensation of monolayers of dl-12HOA, prior to collapse, followed by a different manner of hydrogen bonding. Electron microscope observation gave strong ...

Taro Tachibana

Papers

Chiral Mesophases of 12-Hydroxyoctadecanoic Acid in Jelly and in the Solid State. I. A New Type of Lyotropic Mesophase in Jelly with Organic Solvents

A methode for preparing an aqueous colloidal dispersion of organic materials by using water-soluble polymers: Dispersion ofΒ-carotene by polyvinylpyrrolidone

Enantiomorphism in the Helical Aggregate of Lithium 12-Hydroxystearate

Studies of Helical Aggregates of Molecules. I. Enantiomorphism in the Helical Aggregates of Optically Active 12-Hydroxystearic Acid and Its Lithium Salt

Monolayer Studies of Chiral and Racemic 12-Hydroxyoctadecanoic Acids