Nobuyuki Harada

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Attempts to fabricate mechanical devices on the molecular level have yielded analogues of rotors, gears, switches, shuttles, turnstiles and ratchets. Molecular motors, however, have not yet been made, even though they are common in biological systems. Rotary motion as such has been induced in interlocked systems and directly visualized for single molecules,(More)
2',4'-Dihydroxy-3',5'-dimethyl-6'-methoxychalcone 1, its isomeric flavanone 5-O-methyl-4'-desmethoxymatteucinol 2 and 2'4'-dihydroxy-6'-methoxy-3'-methylchalcone 3 were isolated from the leaves of S. samarangense using a bioassay-directed scheme. In an oral glucose tolerance test, at a dosage of 1.0 mg/20 g mouse, 1 and 2 significantly (alpha = 0.05)(More)
The chiral recognition mechanism of a cinchona alkaloid-based chiral stationary phase (CSP) showing high enantiomer discrimination potential for 2-methoxy-2-(1-naphthyl)propionic acid (MalphaNP acid) was investigated. Conformational and structural analyses of the 1:1 complexes of 9-O-(tert-butylcarbamoyl) quinine selector (SO) and MalphaNP acid (selectand,(More)
This paper estimates new Keynesian, dynamic stochastic general equilibrium models in a liquidity trap (the non-negativity constraint on short term nominal interest rates) using the Monte Carlo particle filter, proposed by Kitagawa (1996) and Gordon et al. (1993), and a self-organizing state space model, proposed by Kitagawa (1998). In our method, we(More)
Symplectin is a photoprotein containing the dehydrocoelenterazine (DCL) chromophore, which links to a cysteine residue through a covalent bond with the emission of blue light. This study focuses on the stereochemical process of the emerging stereogenic centers. Two isomeric fluorinated DCL analogs (2,4-diF- and 2,6-diF-DCL) were employed owing to their(More)
To determine the absolute configuration of chiral compounds, theoretical calculations of ECD spectra have been extensively carried out, where the shape of component CD Cotton effects was approximated by the Gaussian distribution curve. However, in some articles, errors are found in the equations of Gaussian curve expressing CD Cotton effects. In this short(More)
To determine the absolute configurations of chiral compounds, many spectroscopic and diffraction methods have been developed. Among them, X-ray crystallographic Bijvoet method, CD exciton chirality method, and the combination of vibrational circular dichroism and quantum mechanical calculations are of nonempirical nature. On the other hand, X-ray(More)
Prodigiosins are natural red pigments that have multi-biological activities. Recently, we discovered a marine bacterial strain, which produces a red pigment. Extensive two-dimensional nuclear magnetic resonance and mass spectrometry analysis showed that the pigment is a prodigiosin analogue (PG-L-1). Here, we investigated the effect of PG-L-1 on NADPH(More)
Two new polyacetylenic acids, corticatic acids D (2) and E (3), have been isolated from the marine sponge Petrosia corticata along with the known corticatic acid A (1) as geranylgeranyltransferase type I (GGTase I) inhibitors. Their structures were elucidated on the basis of spectroscopic and chemical methods. Compounds 1-3 inhibited GGTase I from Candida(More)
Enantiopure phthalides 2 and 5-8 were synthesized via enantioresolution of the corresponding alcohols with a chiral auxiliary of camphorsultam dichlorophthalic acid, (1S,2R,4R)-(-)-CSDP acid 3, followed by solvolysis with KOH in MeOH and the catalytic oxidation of chiral glycols with iridium complex 28. The absolute configurations of phthalides 2 and 5-8(More)