We developed a short-step synthesis of 2,4,10-triazapyrenes involving two sequential C-H substitutions: Pd-catalyzed cross-coupling reactions via C-H arylation followed by intramolecular Cucatalyzed C-H functionalization. This method was successfully applied to the preparation of 4,10-diaza-, 1,4,10-triaza-, and 1,3,4,10-tetraazapyrenes. Crystal structure analysis of 5,9-di(4-methylphenyl)-2,4,10triazapyrene showed that planar triazapyrene cores have π-stack packing. Incorporating nitrogen atoms into the pyrene framework bathochromically shifted the lowest energy onsets of the absorption bands and increased the first reduction potentials. The nitrogen-containing pyrenes showed fluorescence with weaker intensity (Φf = 0.041-0.12) than parent pyrene. The number and position of nitrogen atoms influenced the extents of these effects.
Intracranial pressure was increased with several procudures. Under the normal conditions of intracranial pressure alkaline phosphatase activity was only in vascular system of cerebrum of dogs and rats. In cerebrum of rabbits moderate activity of the enzyme was seen in the stromal substance of cerebral corters and brain stem and no activity in vascular system. In the brain tissue of animals with increased intracranial pressure alkaline phosphatase activity was much decreased. The rate of decrease in theenzyme activity was proportional with the increase in the intracranial pressure.
DiscussionDr. Sano: Did you use any definite portions of the brain? Did the reactions take place in any lobes of cerebral cortex identically? Dr. Omura: In the preseut studies, frontal, occipital and temporal lobes and Ammon horn were observed, and the reactions were generally strongest in Ammon horn. In the case of the meningitis, the inflammatory meninges ofcerebral basis and cerebellum prominently decrease acid-and alk-p-ase activities since early stage, and then, the activities of cerebral cortex decrease.
Shock absorbers are vital devices for high speed driving with pneumatic cylinders and it is important to select the suitable shock absorbers to use pneumatic systems without trouble. It is commonly believed that the absorbed energy by the shock absorber is the sum of kinetic energy and thrust energy, which are important parameters to set up the pneumatic system. In a typical selecting method of the shock absorber, the value of thrust energy is estimated from the value of only supply pressure. However, the selecting method has been regulated for hydraulic systems and the estimated value of thrust energy in the pneumatic systems is not approximate, because inner pressures in the pneumatic cylinder is not stable and quite different from the supply pressure. Finally there are many bad combinations of the cylinder and shock absorber in the pneumatic system. In the research, we experimentally investigate the formula for estimation of the thrust energy, which is defined in the selecting method of shock absorbers. Experimental results show that accuracy of the formula to select the shock absorber is inefficient. Additionally we examine on parameters that affect the thrust energy and compensate the formula.
A series of triazabenzo [a]pyrenes comprising a cata-condensed pyridine ring and 4,10-diazapyrene framework were synthesized from commercially available materials in the following three steps: palladium-catalyzed direct CÀ H arylation, nucleophilic addition of Grignard reagents to cyano groups, and copper-catalyzed oxidative CÀ N bond formation. The triazabenzo[a]pyrenes showed superior electron-accepting properties and narrower HOMO-LUMO energy gaps compared to the corresponding 4,10-diazapyrene derivative because of the condensation of an electron-deficient pyridine ring. The photophysical, acid-responsive, and electrochemical properties of triazabenzo[a]pyrenes depend on the position of the nitrogen atom in the cata-condensed pyridine ring. Density functional theory calculations revel that the condensation of a pyridine ring leads to a lowering of the LUMO energy level thereby enhancing the electron-accepting properties.
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