Ken’ichi Takeo

Complexes of Starchy Materials with Organic Compounds

Complexes of amylose with several kinds of n-aliphatic ketones having different chain lengths, different positions and numbers of carbonyl groups in the molecules were prepared. The unit cell dimensions of the complexes were calculated in both the wet and dried states by means of X-ray diffraction analysis. Both the 61- and 71-helix amyloses were presented in these complexes. It was found that the helix packing diameter of the amylose-ketone complex changes depending upon the linear chain length of the ketone molecule complexed.

Complexes of Starchy Materials with Organic Compounds:Part II. Complex Formation in Aqueous Solution and Fractionation of Starch by l -Menthone

More than one hundred organic compounds have been examined with respect to their precipitation abilities for starch. All the precipitates may be caused subsequent to complex formation between amylose and reagents. A slight change in molecular structure of the reagent often results in a marked change of the complex formation. The complicated nature of the complex formation is discussed. Some of naturally ocurring monoterpenes, especially l-menthone, showed superior properties as selective precipitants for amylose. So the fractionation of starch was attempted using l-menthone and a good result was obtained.

Complexes of starchy materials with organic compounds part III. X-ray studies on amylose and cyclodextrin complexes

X-Ray analyses of the complexes of amylose with various organic compounds were carried out. Only two kinds of diffraction patterns were observed in the dried state. The first one corresponds to the helix of amylose consisting of six glucose residues per helical turn (61-helix) and the second to that consisting of seven glucose residues (71-helix). The 71-helix was obtained with a relatively wide range of the size of the complexing agents, 4.5~6.0 A in diameter of cross section. Mutual transitions between both helices were made possible by displacing the contained agent with one of the other kinds. During the transition courses, the helix with a fractional number of glucose residues could not be seen. It is, hence, infered that the helix is stabilized by hydrogen bonds between individual helical loops. The diffraction patterns of cyclodextrin complexes were also examined. Under suitable conditions α- and β-dextrins can produce complexes having analogous crystalline structures of 61-helix and 71-helix amylo...

Complexes of Starchy Materials with Organic Compounds:Part IV X-Ray Diffraction of γ-Cyclodextrin Complexes

The crystal structure of γ-cyclodextrin complexes with several organic compounds have been investigated by X-ray powder method. A two-dimensional tetragonal unit cell having a=b=27.2 A and a two-di...

Syntheses of Terpenes by the Condensation of Aliphatic Compounds: Part II. Self-Condensation of Mesityloxide and Structures of Isomeric Isoxylitones

Treatment of mesityloxide with basic condensing agents resulted in formation of isoxylitones-A, B, C and D and isophorone. These compounds were purely isolated and assigned their structures from spectroscopic and chemical evidences. Isoxylitone-A and isoxylitone-B were conformers of 1-acetyl-2, 4, 6, 6-tetramethyl-1, 3-cyclohexadiene separated by the rotational barrier of acetyl group and interconversional barrier of cyclohexadiene ring. Isoxylitone-C was 4-isopropenyl-1, 5, 5-trimethyl-1-cyclohexen-3-one. Isoxylitone-D was 5, 5-dimethyl-3-(1-isobutenyl)-2-cyclohexen-1-one.

Syntheses of Terpenes by the Condensation of Aliphatic Compounds: Part I. Synthesis of Piperitenone by the Condensation of Mesityloxide with 4-Diethylaminobutanone-(2)

The condensation of mesityloxide with 4-diethylaminobutanone-(2) in the presence of potassium t-butoxide gave the products containing piperitenone together with isoxylitones, which were identified by gas chromatography and chemical methods. The effects of the combination of condensing agent, solvent, molar ratio of reagents and reaction temperature on the components in the condensation products were studied. It was found that piperitenone was able to obtain in an yield of 51% on the basis of 4-diethylaminobutanone-(2) by the use of Triton-B as a condensing agent. Also piperitenone can be isolated from the condensation products by the treatment with semicarbazide.