Preparation of Pie‐Shaped and Rugged Aromatic Polyamide Particles

Aromatic polyamide particles were prepared by reacting diamines and diacid chlorides in a reaction solution containing water. They consisted of submicron‐sized pie‐shaped or rugged spherical particles with a narrow size distribution. The surface morphology of these particles was found to vary with the volume of water added, the reaction solvent, and the monomer concentration, but the degree of crystallinity of the particles obtained was almost the same. In addition, the molecular weight of the resulting material depended on the volume of water added and the monomer concentration. During the particle formation process, the degree of crystallinity was set at the initial stage, and thereafter the morphology and the molecular weight changed gradually with reaction time.

     

Preparation of nano-sized polybenzimidazole and carbon particles via poly(amino-amide) particles

Poly(amino-amide; PAA) particles consisting of p-phthalyl chloride and 3,3′-diaminobenzidine and 4,4′-diphenyldicarbony chloride and 3,3′-diaminobenzidine were prepared. The particles were then transformed by treatment with heat into poly(p-phenylenebenzimidazole; PPC–PAA) and poly(4,4′-diphenylenebenzimidazole; DPC–PAA) particles, respectively. The number ratio of ring-closing of the obtained product was found to be dependent on the processing temperature. However, the morphology and diameter of the products were not found to be temperature dependent. PPC–PAA particles were amorphous and DPC–PAA particles had a high degree of crystallinity. Further, upon heating up to 1,000 °C, poly(p-phenylenebenzimidazole) and poly(4,4′-diphenylenebenzimidazole) particles were transformed into carbon particles and carbon bulk, respectively. The poly(amino-amide), polybenzimidazole and carbon particles obtained were nano-sized spherical particles with narrow size distributions.     

Medicinal flowers. XXIII. New taraxastane-type triterpene, punicanolic acid, with tumor necrosis factor-alpha inhibitory activity from the flowers of Punica granatum

The methanolic extract from the flowers of Punica granatum L. (Punicaceae) was found to show inhibitory effect on tumor necrosis factor-alpha (TNF-alpha, 1 ng/ml)-induced cytotoxicity in L929 cells. By bioassay-guided separation, a new taraxastane-type triterpene, punicanolic acid (1), was isolated from the active fraction (ethyl acetate-soluble fraction) together with four triterpenes (2--5), two galloyl glucoses (6, 7), two flavones (8, 9), and beta-sitosterol. Among the constituents, 1, oleanolic acid (2), maslinic acid (4), 1,2,6-tri-O-galloyl beta-D-glucopyranoside (6), 1,2-di-O-galloyl-4,6-O-(S)-hexahydroxydiphenoyl beta-D-glucopyranoside (7), and luteolin (8) significantly inhibited TNF-alpha-induced cytotoxicity in L929 cells at 30 microM.     

Regio- and stereoselective homocoupling of gamma-arylated tert-propargyl alcohols with liberation of a ketone molecule and successive cyclization to produce fluorescent dihydrofuran derivatives

1,1-Disubstituted 3-aryl-2-propyn-1-ols undergo unprecedented regio- and stereoselective homocoupling with liberation of a ketone molecule in the presence of a rhodium catalyst to give the corresponding 2-hydroxymethyl-(E)-enynes. The subsequent cyclization of the enynes in the presence of a base affords fluorescent 2,3-dihydrofuran derivatives.     

Spin-crossover cobalt(II) compound with banana-shaped structure

A banana-shaped spin-crossover (SCO) cobalt(II) complex [Co(C16-terpy)2](BPh4)2 (1) with long alkyl chains, based on a terpyridine frame, was synthesized. Compound 1 exhibited very gradual SCO behavior and changes in the dielectric constant. This shows a way in which SCO materials can be used in electronic devices.     

Total Synthesis of (±)‐Integrifolin

The total synthesis of (±)‐integrifolin has been achieved for the first time through the stereoselective preparation of the bicyclo[5.3.0]decane skeleton based on the tungsten‐catalyzed cyclization of acyclic trienynes under photoirradiation conditions. Further key transformations of the cyclized product are the Tamao oxidation through cyclic silyl ether, the introduction of two oxygen functionalities by the oxidation of the diene and the construction of three exo‐methylene moieties.     

Phase transition and crystal growth of a titania layer on a titanium metal plate

Research on Chemical Intermediates - A titanium metal surface was heated with an alkali metal chloride in order to produce a phase transition from amorphous titania to crystalline titania on the...