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Nucleophilic addition-elimination reactions of 2-methylsulfonyl-1,3-azoles with active methylene compounds were investigated in order to compare the reactivity of substrates. The order of oxasole > thiazole >> N-methylimidazole in the reactivity was exhibited clearly. Furthermore, in oxazole and thiazole series, the predominant reactivity of the 2-position over the 4- and 5-positions was indicated on the reaction with the carbanions generated from active methylene compounds

The syntheses and reactions of pyrimidines N-oxides are reviewed. Pyrimidines having alkyl, aryl, and alkoxyl groups are convertible to their mono-N-oxides by N-oxidation with an organic peroxy acid. The position of the N-oxide group can be elucidated by physical methods. Pyrimidine N-oxides are highly reactive to various nucleophilic reagents owing to their π-deficient character. The reactivity of a methyl group enhanced by introducing an N-oxide group and the characteristic ring-cleavage of N-oxides are also described

A number of 2-substituted 4,5-diphenylthiazoles were synthesized by the nucleophilic substitution of 2-methylsulfonyl-4,5-diphenylthiazole with various sodium alkoxides, amines, and carbanions of active methylene compounds. 2-Methylsulfonyl-4,5-diphenylthiazole was obtained by the potassium permanganate oxidation of 2-methylthio-4,5-diphenylthiazole in the presence of a phase-transfer catalyst. 2-Ethoxy-4,5-bis(4-methoxyphenyl) thiazole was prepared in a similar manner. 2-Ethynyl-4,5-diphenylthiazoles were synthesized by the palladium catalyst cross-coupling reaction of 2-iodo-4,5-diphenylthiazole with monosubstituted acetylenes. These compounds were tested for inhibitory activity against blood platelet aggregation in vitro. Among them, 2-alkoxy-, and 2-(4-methylpiperazin-1-yl)-4,5-diphenylthiazole were found to have potent inhibitory activity.

Title reaction is well prompted by the catalytic action of dichlorobis(triphenylphosphine)palladium in dimethylformamide in the presence of tetraethylammonium chloride to give (Z)-1-ethoxy-2-(4-substituted phenyl)ethene. The method is also useful for the introduction of a 2-ethoxyethenyl moiety into heteroaromatic rings such as pyridine, thiophene, indole

3-Substituted 5-(tributylstannyl)isoxazoles were synthesized in good yields by the 1,3-dipolar cycloaddition reaction of ethynyltributylstannane with nitrile oxides generated in situ . 3-Methyl-5-(tributylstannyl)isoxazole was easily converted to the corresponding 5-benzoyl- and 5-arylisoxazoles by the palladium-catalyzed reaction.

4-Chlorothieno[2,3-d]pyrimidines were prepared by the chlorination of 4-oxo-3,4-dihydrothieno[2,3-d]pyrimidines with phosphoryl chloride. 4-Oxo-3,4,5,6,7,8-hexahydro[1]-benzo- and 4-oxo-6-phenylthieno[2,3-d]pyrimidine were synthesized by the cyclization of 2-acylaminothiophene-3-carboxamide derivatives with base. 2-Methyl-4-oxo-3,4-dihydrothieno[2,3-d]pyrimidine was prepared by the treatment of 2-methyl-4-trichloromethylthieno-[2,3-d]pyrimidine with sodium hydroxide in aqueous methanol. A series of 4-alkylamino- and 4-arylaminothieno[2,3-d]pyrimidines were synthesized by the nucleophilic substitution of 4-chlorothieno[2,3-d]pyrimidines with various amines. These compounds were evaluated for antifungal activity against Piricularia oryzae. The preventive effects on Rice blast, Sheath blight, and Cucumber powdery mildew were also determined by pot tests.

A number of 2-substituted 4,5-diphenylthiazoles were synthesized by the nucleophilic substitution of 2-methylsulfonyl-4,5-diphenylthiazole with various sodium alkoxides, amines, and carbanions of active methylene compounds. 2-Methylsulfonyl-4,5-diphenylthiazole was obtained by the potassium permanganate oxidation of 2-methylthio-4,5-diphenylthiazole in the presence of a phase-transfer catalyst. 2-Ethoxy-4,5-bis(4-methoxyphenyl) thiazole was prepared in a similar manner. 2-Ethynyl-4,5-diphenylthiazoles were synthesized by the palladium catalyst cross-coupling reaction of 2-iodo-4,5-diphenylthiazole with monosubstituted acetylenes. These compounds were tested for inhibitory activity against blood platelet aggregation in vitro. Among them, 2-alkoxy-, and 2-(4-methylpiperazin-1-yl)-4,5-diphenylthiazole were found to have potent inhibitory activity.

The effect of W and W2C on the synthesis of multi-walled carbon nanotubes (MWCNTs) by hot-filament-assisted chemical vapor deposition (HFCVD) using Co particles as a catalyst was examined. W or W2C was vacuum-evaporated onto Co particles supported by zeolite and used as a catalyst in CNT synthesis. Methanol was used as a carbon source. Synthesis of CNTs was carried out at about 400°C. The density of the MWCNTs synthesized using only Co as a catalyst was the lowest, and was sequentially higher when using Co combined with W (Co + W) and Co combined with W2C (Co + W2C). The mechanism of the enhancement of CNT growth upon the addition of W or W2C was considered.

Ultrasonic three-dimensional (3-D) image sensing in air is successfully demonstrated by combining a novel thermally induced ultrasonic emission from nanocrystalline porous silicon (nc-PS) device with a condenser microphone array. The nc-PS ultrasonic emitter is composed of a patterned heater electrode, an nc-PS layer, and a single-crystalline silicon (c-Si) substrate. In this device, an ideal probe signal can be generated with little reverberation under impulse operation, since the acoustic output shows a flat frequency response in a wide range due to a quick thermo-acoustic conversion at the device surface without any mechanical vibrations. The 3-D object is detected with a spatial resolution considerably higher than that in the case of conventional techniques based on piezoelectric transducers. It is also shown that the device is available for the detection of several objects with different acoustic reflectance coefficients.

Rigidin, a marine alkaloid, was synthesized by the combination of acylation via lithiation and arylation by palladium-catalyzed reaction starting from 2,4-dimethoxypyrrolo[2,3- d ]pyrimidine.

Methyl α-methoxyarylacetates 3 have been synthesized by the palladium-catalysed reaction of iodobenzenes 1 with α-methoxyketene methyl silyl acetals 2. The diastereoselective and enantioselective synthesis of the arylacetates has also been examined.

[1] The corner frequency, fC, and the seismic moment, M0, of microearthquakes (local magnitude from −1.3 to 1.3) are estimated from the records of sensors located at an 1800-m-deep borehole at the Nojima fault, central Japan. The digital waveforms of each event are recorded with two different sampling rates, 10 kHz and 100 Hz. The source parameters estimated from high-sampling data satisfy a relationship of M0 ∝ fC−3, corresponding to a constant stress drop law, while those calculated from low-sampling data follow a relationship of M0 ∝ fC−4. A lack of high frequency components in the 100 Hz sampling data seem to be obvious, indicating that the value of fC and M0 are incorrectly estimated and the relationship of M0 ∝ fC−4 is an artifact caused by the limited frequency band of these data. The scaling relationship of M0 ∝ fC−3 is, thus, also valid for microearthquakes, and the breakdown of the constant stress drop law, reported in the literature, is not well founded.

Indolylzinc derivatives were prepared by the oxidative addition of active zinc to iodoindoles, which coupled with aromatic halides in the presence of palladium catalyst to give arylated indoles.

The oxidative addition of active zinc to bromo- and iodopyridines gave pyridinylzinc halides which were coupled with aryl halide or benzoyl chloride in the presence of a palladium catalyst.

Indolylzinc halides are prepared by two methods: transmetallation of indolyllithiums with zinc chloride and oxidative addition of active zinc to iodoindoles. The palladium-catalysed reaction of the indolylzinc halides provides a practical method for synthesizing arylindoles.

The marine alkaloid rigidin has been synthesized from 2,4-dimethoxy-7-phenylsulfonylpyrrolo[2,3-d]pyrimidine. Lithiation of the pyrrolo[2,3-d]pyrimidine followed by electrophilic substitution with N, 4-dimethoxy-N-methylbenzamide afforded a 6-(4-methoxy)benzoyl derivative which by alkaline hydrolysis and subsequent iodination was converted into 2,4-dimethoxy-5-iodopyrrolo [2,3-d] pyrimidin-6-yl 4-methoxyphenyl ketone. The palladium-catalysed arylation of this with 2-(4-methoxyphenyl)-1,3,2-dioxaborinane followed by demethylation with boron tribromide gave rigidin.

Photochemical reactions in 10 GeO(2)-90 SiO(2) glass induced by irradiation with excimer lasers (KrF, 5.0 eV, XeCl, 4.0 eV) and a Hg lamp (4.9 eV) were examined. The irradiation with excimer lasers generated two types of paramagnetic defect, an electron-trapped center associated with fourfold coordinated Ge ions and a self-trapped hole center on bridging oxygen. Taking the optical band gap (~7.1 eV) of the glass obtained in this work and the power density of laser pulses [10-90 mJ/(cm(2) pulse), pulse duration 20 ns] into account, we concluded that these centers were formed by band-to-band excitation by two-photon absorption process. On the other hand, the lamp illumination ( 16 mW/cm(2)) caused the formation of Ge E' centers from preexisting oxygen-vacancy-type defects by the one-photon absorption process. These two kinds of reaction proceed independently, depending on the power densities of UV beams, at least in our experimental condition.

1,3-Dipolar cycloaddition reaction of trimethylstannylacetylene with phenyl azide gave a regioselective product, 1-phenyl-4-trimethylstannyl-1,2,3-triazole. On the other hand, the reaction of trimethylstannyl-1-hexyne, -phenylacetylene, and -trimethylsilylacetylene with the azide yielded a mixture of the corresponding 4- and 5-trimethylstannyl-1-phenyl-1,2,3-triazoles. Detrimethylstannylation, iodination, benzoylation, and palladium-catalyzed phenylation of 4-trimethylstannyl- and 4,5-bis(trimethylstannyl)-1-phenyl-1,2,3-triazoles were also described

3-Methyleneindoline derivatives were synthesized by intramolecular Heck reaction of N-allyl-2-iodoaniline derivatives in the presence of Ag2Co3. This method was successfully applied to the synthesis of the CC-1065/duocarmycin pharmacophore.

Methyl 2-(nitrogen-heteroaryl)propanoates were synthesized by the palladium-catalyzed reaction of heteroaryl halides with (E)-1-methoxy-1-trimethylsiloxypropene

1,3-Dioxep-5-ene was arylated by using Heck reaction, and the arylated 1,3-dioxep-4-ene derivatives were easily converted into 4-arylbutyrolactones, intermediates for the synthesis of natural products and biological active compounds

2-Arylindoles were synthesized by the palladium-catalyzed reaction of aryl halides with 2-indolylzinc derivatives which were derived from the lithio derivatives

1,3-Dipolar cycloaddition reaction of diazomethane and ethyl diazoacetate with tributylstannyl-acetylenes occurred regioselectively to afford the corresponding 3(5)-tributylstannylpyrazoles. The cycloaddition reaction of 3-phenylsydnone with the stannylacetylenes proceeded also regioselectively, and 3-tributylstannyl-1-phenylpyrazoles were isolated. 4-Tributylstannyl- and 5-tributylstannyl-1-phenylpyrazole were prepared by the stannylation of 4-lithio- and 5-lithio-1-phenylpyrazoles with tributylstannyl chloride. Iodination, benzoylation, and phenylation of the stannylpyrazoles were examined

Four kinds of 1 H-pyrrolopyridines having no substituent were simply and easily synthesized by the palladium-catalyzed reaction of easily available nitropyridine derivatives with (Z)-1 -ethoxy-2-tributylstannylethene as a key reaction

The synthesis of methyl 6-alkylamino-3-pyridazinecarboxylates (4a-c) was accomplished by the following reaction sequence. On treatment of methyl 6-chloro-3-pyridazinecarboxylate (1) with methanolic ammonia, 6-chloro-3-pyridazinecarboxamide (5) was precipitated almost quantitatively, which reacted with primary alkylamines to give the corresponding 6-alkylamino-3-pyridazinecarboxamide (6a-c). These products were smoothly converted into the methyl esters (4a-c) by treatment with methanol in the presence of boron trifluoride etherate. The reaction of 1 with butylamine in THF gave a complicated mixture in which N-butyl-6-chloro-3-pyridazinecarboxamide(2), N-butyl-6-butylamino-3-pyridazinecarboxamide(3), 4b, and 1 were involved

Inverse electron-demand Diels-Alder reaction of 3,6-disubstituted 1,2,4,5-tetrazines with tributylstannylacetylenes containing a substituent gave 4-(tributylstannyl)pyridazines. Particularly, dimethyl 1,2,4,5-tetrazine-3,6-dicarboxylate gave 4-(tributylstannyl)pyridazines in good yields. Substitution reaction of 3,6-diphenyl-4-(tributylstannyl)pyridazine was also described

Nucleophilic addition-elimination reactions of 2-methylsulfonyl-1,3-azoles with active methylene compounds were investigated in order to compare the reactivity of substrates. The order of oxasole > thiazole >> N-methylimidazole in the reactivity was exhibited clearly. Furthermore, in oxazole and thiazole series, the predominant reactivity of the 2-position over the 4- and 5-positions was indicated on the reaction with the carbanions generated from active methylene compounds

Homolytic chlorination of 5,6-dimethyl-as-triazine with Cl 2 gave 6-dichloromethyl-5-trichloromethyl-as-triazine (I) selectively. Structural determination of I by chemical method and synthesis of 5-amino-6-formyl-as-triazine derivatives are described.

The reaction of 3-bromopyridine with phenylacetonitrile in the presence of NaH in THF gave a simple substitution product, α-phenyl-3-pyridineacetonitrile, whereas the reaction of 5-bromopyrimidine with phenylacetonitrile under similar conditions gave a ring-transformation product, 2-amino-5-bromo-3-phenylpyridine. 3-bromoquinoline and 4-bromoisoquinoline underwent the former type reaction, while 3-bromo- and 3-chloroisoquinolines were converted into 2-amino-3-phenyl-1-naphthalencarbonitrile according to the latter type reaction

The syntheses and reactions of pyrimidines N-oxides are reviewed. Pyrimidines having alkyl, aryl, and alkoxyl groups are convertible to their mono-N-oxides by N-oxidation with an organic peroxy acid. The position of the N-oxide group can be elucidated by physical methods. Pyrimidine N-oxides are highly reactive to various nucleophilic reagents owing to their π-deficient character. The reactivity of a methyl group enhanced by introducing an N-oxide group and the characteristic ring-cleavage of N-oxides are also described

Title reaction is well prompted by the catalytic action of dichlorobis(triphenylphosphine)palladium in dimethylformamide in the presence of tetraethylammonium chloride to give (Z)-1-ethoxy-2-(4-substituted phenyl)ethene. The method is also useful for the introduction of a 2-ethoxyethenyl moiety into heteroaromatic rings such as pyridine, thiophene, indole

The monomethoxyl derivatives of various π-electron-deficient N-heteroaromatics reacted with phenylacetonitrile in tetrahydrofuran in the presence of sodium hydride to give α-phenyl-N-heteroareneacetonitriles in the yields ranging from 45 to 78 %. On the contrary, the reaction of these methoxyl derivatives with ethyl cyanoacetate or malononitrile under similar conditions was restricted within narrow limits. The synthesis of benzoyl-N-heteroaromatics by the air-oxidation of α-phenyl-N-heteroareneacetonitriles was described additionally

This type ring-transformation(intramolecular reverse electron-demand Diels-Alder reaction) was applicable to the corresponding 3,5-diphenyl-1,2,4-triazine-6-carboxylic acid esters. According to the similar manner, benzofuro[2,3-b]pyridines, benzofuro[2,3-c]pyridines, and benzofuro[2,3-d]pyridines were synthesized in satisfactory yields. The Diels-Alder reaction of 3-(2-phenylethynylphenoxy)-1,2,4-benzotriazine afforded 11-phenylbenzofuro[2,3-b]quinoline.

The site-selectivity in the modified Reissert-Henze reaction of 5-substituted, and 4, 5-disubstituted pyrimidine 1-oxides with trimethylsilyl cyanide was examined. The reaction of 5-substituted 4-methoxypyrimidine 1-oxides with trimethylsilyl cyanide gave exclusively 2-pyrimidine-carbonitriles in good yields without exception. On the other hand, the other 5-substituted and 4, 5-disubstituted pyrimidine 1-oxides gave mainly 6-pyrimidinecarbonitriles.

N-Oxidation of pyrimidines having unsymmetrically substituted 4-and 6-positions with hydrogen peroxide in acetic acid gave mixture of their 1-oxides and 3-oxides. Ring transformation of these 1-oxides and 3-oxides into isoxazoles occurred on treatment with mineral acid, and provided information on the position of the N-oxide group in the pyrimidine N-oxides. Nuclear magnetic resonance spectroscopy with a lanthanide shift reagent was also found to be useful in identifying the pyrimidine 1-and 3-oxides.

Treatment of 4-alkoxy-6-methylpyrimidine 1-oxides with acetic anhydride followed by reaction with diketene gave 7-acetyl-4-alkoxy-2-methylisoxazolo[4, 5-c]pyridines and 7-acetyl-4-alkoxy-3-methyloxazolo[4, 5-c]pyridines, respectively. The structure elucidation of these compounds on the basis of spectral data and chemical reactions, and the reaction pathway of the ring transformation are described.

5-Methyl-(4a), 7-methyl-(4b), and 8-methyl-5, 6, 7, 8-tetrahydro-1, 6-naphthyridine (4c) were synthesized by chemical modification of pyridine derivatives. On the other hand, the synthesis of the compounds (20b, c) having a methyl group in the aromatic ring of 5, 6, 7, 8-tetrahydro-1, 6-naphthyridine was accomplished by the condensation of 1-benzyl-4-piperidinone with the corresponding 3-amino-enones followed by debenzylation. The pathway of the condensation is briefly discussed.