A new ring expansion for a chiral hexahydroazulene skeleton possessing an angular methyl group

A new synthetic route for a pseudoguaiane ring system is described. The synthesis features an Ireland-Claisen rearrangement for constructing the trans-fused ring system, followed by a new ring expansion to yield a bicyclo[5.3.0]decane ring system possessing an angular methyl group.     

Pseuduvarines A and B, two new cytotoxic dioxoaporphine alkaloids from Pseuduvaria rugosa

Pseuduvarines A (1) and B (2), two new dioxoaporphine alkaloids with an amino moiety, were isolated from the stem bark of Pseuduvaria rugosa and their structures were elucidated by combination of 2D-NMR spectroscopic analysis. Pseuduvarines A (1) and B (2) showed cytotoxicity against MCF7, HepG2, and HL-60 (1: IC??, 0.9, 21.7, and >50.0 μM, respectively, 2: IC?? >50.0, 15.7, and 12.4 μM, respectively).     

Molecular states of p-dimethylaminobenzonitrile coground with β-cyclodextrin investigated using solid-state fluorescence spectroscopy

Changes in molecular states of p-dimethylaminobenzonitrile (DMABN) coground with β-cyclodextrin (β-CD) were examined using solid-state fluorescence measurements. Formation of a DMABN/β-CD inclusion complex by coprecipitation was confirmed by powder X-ray diffraction measurement. The powder X-ray diffraction pattern of the ground mixture was a halo pattern and differed from the pattern of the mixture prepared by coprecipitation. Solid-state fluorescence measurements revealed emission by DMABN crystals in a twisted intermolecular charge-transfer state at 473 nm. DMABN in the DMABN/β-CD coprecipitate had a fluorescence emission peak at 393 nm due to its planar structure. In contrast, DMABN in a DMABN/β-CD ground mixture had an emission peak at 473 nm due to its twisted structure. Grinding time-dependent structural changes in DMABN were evaluated using fluorescence lifetime and relative quantum yield measurements. Structural changes in DMABN in the DMABN/β-CD coprecipitate from a planar to a twisted structure were observed with grinding. DMABN, dispersed in microcrystalline cellulose (CC) molecules in a DMABN/CC ground mixture, had a fluorescence emission peak at 473 nm. However, the excitation spectrum of a DMABN/β-CD ground mixture differed from that of DMABN in CC. These results indicated that the molecular state of DMABN accommodated in the β-CD cavity differs between the coprecipitate and the ground mixture.     

Synthesis and pharmacological evaluation of 1-alkyl-N-[(1R)-1-(4-fluorophenyl)-2-methylpropyl]piperidine-4-carboxamide derivatives as novel antihypertensive agents

We synthesized and evaluated inhibitory activity against T-type Ca(2+) channels for a series of 1-alkyl-N-[(1R)-1-(4-fluorophenyl)-2-methylpropyl]piperidine-4-carboxamide derivatives. Structure-activity relationship studies have revealed that the isopropyl substituent at the benzylic position plays an important role in exerting potent inhibitory activity, and the absolute configuration of the benzylic position was found to be opposite that of mibefradil, which was first launched as a new class of T-type Ca(2+) channel blocker. Oral administration of N-[(1R)-1-(4-fluorophenyl)-2-methylpropyl]-1-[2-(3-methoxyphenyl)ethyl]piperidine-4-carboxamide (17f) lowered blood pressure in spontaneously hypertensive rats without inducing reflex tachycardia, an adverse effect often caused by traditional L-type Ca(2+) channel blockers.     

Structure and dynamics of polymeric materials in nano-scale

The nano-palpation technique,i.e.,nanometer-scale elastic and viscoelastic measurements based on atomic force microscope,is introduced.It is demonstrated to be very useful in analyzing nanometer-scale materials properties for the surfaces and interfaces of various types of soft materials.It enables us to obtain not only structural information but also mechanical information about a material at the same place and at the same time.     

Highly clear and transparent nanoemulsion preparation under surfactant-free conditions using tandem acoustic emulsification

A new technique for the preparation of a highly clear and transparent emulsified aqueous solution containing immiscible monomer droplets with diameters of a few tens of nanometres under surfactant-free conditions using tandem acoustic emulsification is described. Highly conductive transparent polymer films were successfully prepared from such an emulsified solution.     

Pyrimidine derivatives XII. A convenient preparation of 6-formylpyrimidinedione and 2- and 3-formylpyridine derivatives from corresponding nitrooxymethyl derivatives

The convenient preparation of 6-fomylpyrimidinedione derivatives and 2- and 3-formylpyridine are described. Thus, 5-bromo-1,3-dimethyl- ( 1a ), 5-bromo-3-methyl-1-(2-nitrooxyethyl)- ( 1b ), and 5-bromo-3-methyl-1-(3-nitrooxypropyl)-2,4(1H,3H)-pyrimidine-dione ( 1c ) were converted to the corresponding 6-formyl compounds 2a, 2b , and 2c , respectively, in excellent yields by the reaction with triethylamine and 1,4-diazabicyclo[2.2.2]octane. These 6-formylpyrimidinedione derivatives are key intermediates for the preparation of 6-carbon-carbon substituted compounds, which are expected to be potential antitumor and antiviral agents. Similarly, 2-(and 3-)formylpyridine ( 9a (and 9b )) were obtained by the reaction of 2-(and 3)nitrooxymethylpyridine ( 8a (and 8b )) with 1,4-diazabicyclo[2.2.2]octane.     

Polymerization of (o-methylphenyl)acetylene and polymer characterization

(o-Methylphenyl)acetylene polymerized with high yields in the presence of W and Mo catalysts. W catalysts were more active than the corresponding Mo catalysts. The weight-average molecular weight of the polymer formed with W(CO)₆–CCl₄–hv reached 8 × 10⁵, being higher than the maximum value (ca. 2 × 10⁵) for poly(phenylacetylene). The polymer had the structure $\rlap{--} [{\rm CH} \hbox{=\hskip-1pt=} {\rm C}(o - {\rm CH}_3 {\rm C}_6 {\rm H}_4 )\rlap{--} ]_n $. The stereochemical structure of the main chain could be determined by ¹³C-NMR; the cis content varied in a range of 41–61% depending on the polymerization conditions. The present polymer was thermally more stable than poly(phenylacetylene) according to thermogravimetric analysis. Interestingly, this polymer possessed deeper color than poly(phenylacetylene), and showed a fairly strong absorption in the visible region.     

Analysis of traces of polycyclic aromatic hydrocarbons by adsorption on cobalt phthalocyanine and barium salts of sulphophthalocyanines followed by thermal desorption gas chromatograph

Small amounts of polycyclic aromatic hydrocarbons (PAHs) in aqueous solution were almost completely adsorbed on barium salts of copper (II) sulphophthalocyanines and cobalt (II) phthalocyanine, which were precipitated from the solution. Recoveries of the PAHs from the precipitates by thermal desorption gas chromatography were 71–95%. The method is useful for the concentration and analysis of medium molecular weight, thermally stable PAHs.