Sulfur-containing polymers by the reaction of diphenyl sulfide with sulfur chlorides

The electrophilic reaction of sulfur dichloride with diphenyl sulfide proceeds efficiently at room temperature to yield oligo(phenylene sulfide) in the presence of a catalytic amount of Fe powder. Sulfur dichloride shows higher reactivity than sulfur monochloride. The reaction is promoted through the activation of sulfur dichloride by Fe powder. The polymeric product contains a linear structure linked by disulfide and sulfide bonds.     

Chemical synthesis of phosphorylated tetraacyl disaccharide corresponding to a biosynthetic precursor of lipid A

A total synthesis of 2,2′-N; 3,3′-O-tetraquis[(R)-3-hydroxytetradecanoyl]-β(1–6)-D-glucosamine disaccharide 1,4′-diphosphate is described. This is the first confirmation of the fundamental structure of lipid A since the synthetic compound exhibited most of the characteristic biological activities of natural endotoxin.     

Chromoionophores Based on Crown Ethers and Related Structures for Alkali Metal Ion Sensing in Aqueous Media

Recent progress in chromoionophores based on (1) spherand and hemispherand, (2) cryptand, and (3) dibenzo-16-crown-5 and calix[4]crown which selectively respond to alkali metal ions in aqueous media is reviewed in relation to their molecular structure and photometric function. The design concept of the chromoionophores for colorimetry in aqueous media is discussed in the light of their acid dissociation and metal complex formation equilibria.     

Phenolic constituents in Erythrina x bidwilli and their activity against oral microbial organisms.

Five flavonoid compounds, including two new isoflavanones, were isolated from the root bark of Erythrina x bidwilli. Their structures were determined to be 2,10-di(gamma,gamma-dimethylallyl)-3,9-dihydroxypterocarpan (erythrabyssin II), 6,8-di(gamma,gamma-dimethylallyl)-7,2',4'-trihydroxyisoflavanone (bidwillon A), 8-gamma,gamma-dimethylallyl-2',4'-dihydroxy-[6",6"-di-methylpyrano - (2",3":7,6)]isoflavanone (bidwillon B), 8-gamma,gamma-dimethylallyl-7,4'-dihydroxyisoflavone (8-gamma,gamma-dimethyl-allyldaidzein), and 8-gamma,gamma-dimethylallyl-5,2',4'-trihydroxy-[6",6"-dimethylpyrano+ ++- (2",3":7,6)]isoflavone (auriculatin), by means of spectroscopic analysis. Some potent activities against oral microbial organisms (Fusobacterium nucleatum and Prevotella intermedia) were shown in these flavonoid compounds.     

Inclusion Compound Formation of Amylose by Sealed-Heating with Salicylic Acid Analogues

The inclusion compounds of linear amylose and salicylic acid analogues preparedby sealed-heating were evaluated by using powder X-ray diffraction and infraredspectroscopy. Sealed-heating of amylose and either salicylamide or benzoic acidinduced the amylose structural change from the 6₁- to the 7₁-helix structure, while sealed-heating with o-toluic acid, o-chlorobenzoic acid and o-nitrobenzoic acid induced the change from the 6₁- to the 8₁-helix structure. In contrast to theresults in the salicylic acid system, the amylose helix type of sealed-heated samplewas not varied by the load of the guest compound, but was fixed only by the guestspecies. No change of the helical structure of amylose depending on the amylose molecular weight was observed. From the comparison of inclusion compound formation among different guest systems, it was found that the higher vapor pressure at 100 °C of the guest resulted in faster inclusion compound formation. The vapor pressure of the guest compound would be an important factor affecting the progress of inclusion compound formation.     

The first electroresponsive phenylazomethine macrocycles: highly preferential formation and regular molecular packing

[structure: see text] Highly preferential formation of novel polyphenylazomethine macrocycles was achieved by further addition of TiCl(4) and/or the monomer during the course of the polycondensation. These macrocycles have unique structures based on the (E)/(Z)-conformation of the azomethine bonds, the extremely regular molecular-packing state, and the reversible redox properties by protic acid doping.