Yoshitomi Morizawa

Low-Resonant-Frequency Micro Electret Generator for Energy Harvesting Application

A vibration-driven electret generator has been developed for energy harvesting applications. By using parylene as the spring material, a low-resonant-frequency MEMS generator is realized. Electrostatic levitation is adopted for the gap control. Large in-plane amplitude of 0.5 mm at the resonant frequency as low as 21 Hz has been achieved. We also demonstrate electret-powered operation of LED using a low-power-consumption impedance conversion circuit.

Trifluoromethyl group induced highly stereoselective synthesis of α-hydroxy carbonyl compounds

Abstract The reaction of enolate prepared from ethyl 3-methyl-4,4,4-tri-fluorobutyrate with MoO5-Py-HMPA complex provides ethyl (2S★,3S★)-2-hydroxy-3-methyl-4,4,4-trifluorobutyrate predominantly. In contrast, NaBH4 reduction of the corresponding 2-oxobutyrate affords (2R★, 3S★)-hydroxyester preferentially.

7,7-Difluoroprostacyclin derivative, AFP-07, a highly selective and potent agonist for the prostacyclin receptor

Recently, we cloned cDNAs for the prostacyclin receptor (IP) and the four mouse PGE receptor subtypes, EP1, EP2, EP3, and EP4, and established Chinese hamster ovary cells that stably express each receptor. We examined the agonist potency and selectivity of AFP-07, a 7,7-difluoroprostacyclin derivative, compared with widely used stable prostacyclin analogue, iloprost, using the cells expressing each cloned receptor. AFP-07 strongly displaced the [3H] iloprost binding to the IP receptor-expressing cell membranes, the half maximal concentration for the displacement being 3 nM, which was one order lower than that of iloprost. AFP-07 concentration-dependently stimulated cAMP formation in the IP-expressing cells, the half-maximal concentration for the stimulation being 10 pM, which was one order lower than that of iloprost. On the other hand, AFP-07 showed lower affinity for EP1, EP2, EP3, and EP4 than PGE2, but iloprost had the same affinity as PGE2 for the EP1, These results demonstrate that AFP-07 is a potent and highly selective agonist for the IP receptor.

Nano-cluster-enhanced high-performance perfluoro-polymer electrets for energy harvesting

Development of high-performance electret materials is required to obtain a large power output of the electrostatic vibration-driven energy harvesters. In this study, by introducing aminosilane derivatives into CYTOP-based perfluorinated polymer film, we have successfully formed nano-clusters containing the organic siloxanes in the polymer electrets. Using small-angle x-ray scattering, tapping mode AFM and SEM analysis, the existence of such nano-clusters has been directly observed in the CYTOP film. It is suggested that the observed nano-clusters serve as the charge trap site and enhance the surface charge density and the thermal stability of the trapped charges. As a polymer electret, an extremely high surface charge potential of −1.6 kV with the 15 µm thick film has been obtained under the optimum condition of corona charging.

Ruthenium-Catalyzed Olefin Cross-Metathesis with Tetrafluoroethylene and Analogous Fluoroolefins

This Communication describes a successful olefin cross-metathesis with tetrafluoroethylene and its analogues. A key to the efficient catalytic cycle is interconversion between two thermodynamically stable, generally considered sluggish, Fischer carbenes. This newly demonstrated catalytic transformation enables easy and short-step synthesis of a new class of partially fluorinated olefins bearing plural fluorine atoms, which are particularly important and valuable compounds in organic synthesis and medicinal chemistry as well as the materials and polymer industries.

A novel trifluoromethanesulfonamidophenyl-substituted quinoline derivative, GA 0113: synthesis and pharmacological profiles

Abstract The trifluoromethanesulfonamidophenyl-substituted quinoline GA 0113 have been synthesized from o-nitrobenzoyl chloride via a multi-step process. GA 0113 displaced specific binding of [ 125 I] -Sar1, Ile8-Ang II to AT1 receptors in membrane from Sf9 cells. In concious normotensive dogs, GA 0113 inhibited the Ang II-induced pressor response with ID50 of 0.032xa0mg/kg and dose-dependently increased plasma renin activity for 48xa0h.

SYNTHESIS OF 7-FLUORO-2,4-METHYLENE-17,20-DIMETHYLPROSTACYCLINS. NOVEL STABLE PROSTACYCLIN ANALOGS AS POTENT ANTI-ANGINAL AGENTS

Abstract Synthesis of new stable fluoroprostacyclins, 7-fluoro-2,4-methylene-17, 20-dimethylprostacyclins (1,2) with potent and long-lasting anti-anginal activities has been achieved. The cyclobutylene prostaglandin skeleton 10 was constructed efficiently according to three-component coupling reaction. Stereospecific fluorination of silyl ether 11 and subsequent cyclization of the fluoride 12 successfully provided the desired 7-fluoro-2,4-methylene-17,20-dimethylprostacyclin.

Pharmacologic profiles of GA0113, a novel quinoline derivative angiotensin II AT1-receptor antagonist.

GA0113 is a newly developed angiotensin II (Ang II) AT1-receptor antagonist having a quinoline moiety. This study was undertaken to clarify the pharmacologic profile of GA0113. In vitro profiles of GA0113 for Ang II receptors were examined in a receptor-binding assay and an Ang II-induced vasoconstriction study. Antihypertensive effects after single or repeated oral administrations were examined in conscious renal hypertensive (RH) or spontaneous hypertensive (SH) rats. Blood pressure (BP) and heart rate were measured by the tail-cuff method. GA0113 interacted with AT1 receptors in a competitive manner, but showed an insurmountable antagonistic action in Ang II-induced vasoconstriction. In RH rats, GA0113 (0.01-1 mg/kg) reduced BP with ED25 values of 0.015 mg/kg, and required 0.1 mg/kg for 24-h BP control. Repeated administration of GA0113 in SH rats (0.03-0.1 mg/kg) showed moderate onset and gradually potentiated reduction of BP, which reached a plateau after day 4 of treatment without alteration in heart rate. There was no tolerance of the hypotensive action or rebound phenomenon after cessation of the treatment. In pharmacokinetic studies, GA0113 shows excellent oral bioavailability (94%) and a long circulating half-life (12 h) in rats. These findings indicate that GA013 may serve as a highly potent and effective antihypertensive agent in humans. GA0113, with its unique chemical structure and pharmacologic and pharmacokinetic profiles may provide new possibilities in hypertension therapy.

Synthesis of new stable fluoroprostacyclin analogs with potent anti-anginal activity

Abstract Synthesis of new stable fluoroprostacyclins, 7-fluoro-2,4-methylene-17,20-dimethylprostacyclins ( 1, 2 ) with potent and long-lasting anti-anginal activities has been achieved via three-component coupling reaction and stereospecific fluorination.

Diethynyl naphthalene derivatives with high ionization potentials for p-channel and n-channel organic field-effect transistors

We have developed and characterized diethynyl naphthalene derivatives with high ionization potentials, 2,6-bis [(naphthalen-2-yl)ethynyl]-naphthalene (BH-202) and 2,6-bis[(heptafluoronaphthalen-2-yl)ethynyl]-naphthalene (BF-202) for new organic semiconductors. Using x-ray diffraction, we have found that thin films of the two organic semiconductors have a high degree of molecular order. Organic field-effect transistors (OFETs) with BH-202 films showed p-type characteristics. By the optimization of the fabrication process, the device exhibited a high field-effect hole mobility up to 0.12 cm2 V−1 s−1 and a high on/off current ratio of 3.3 × 105. On the other hand, OFETs with BF-202 films showed n-type characteristics. The field-effect electron mobility was calculated to be 3.4 × 10−3 cm2 V−1 s−1 and the on/off current ratio was 5.4 × 103.