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Shinji Murai

Publications and source records attributed to Shinji Murai.

14 recordsLinked to original sources
PubMed2004

Expression and localization of membrane-type-1 matrix metalloproteinase, CD 44, and laminin-5gamma2 chain during colorectal carcinoma tumor progression.

Membrane-type-1 matrix metalloproteinase (MT1-MMP) is overexpressed in many malignant tumor tissues and would be involved in tumor-cell migration. Using dual immunofluorescence of frozen sections, this study examined the expression and localization of MT1-MMP and its interacting molecules, CD44 and laminin-5gamma2 chain (LN-5gamma2) monomer, in 48 cases of colorectal tumors. Recent studies have shown that MT1-MMP, CD44 and LN-5gamma2 are direct downstream targets in the adenomatosis polyposis coli (APC)/beta-catenin (Wnt)-signaling pathway, which is upregulated in most colorectal epithelial tumors. MT1-MMP overexpression was observed in adenocarcinoma cases with moderate and/or less differentiation coinciding with CD44 downmodulation. Recent observations indicate that MT1-MMP overexpression disrupts tubulogenesis of MDCK cells in type-I collagen-rich tissues. Therefore, MT1-MMP overexpression might involve disturbances of neoplastic glandular structures during colorectal adenocarcinoma tumor progression. Intensity distribution analyses of images with dual immunofluorescence indicated that overexpressed MT1-MMP is closely associated with the enhanced expression of the LN-5gamma2 monomers at the invasive front of dedifferentiated tumor cells. Additionally, the graded expression of nuclear active beta-catenin was found in moderately differentiated and dedifferentiated areas of adenocarcinomas, where MT1-MMP overexpression was observed. Therefore, this study reveals that MT1-MMP might be a major effector of Wnt signaling in the late stage of colorectal carcinoma tumor progression.

Biomarkers, Tumor↗
PubMed2004

Ruthenium-catalyzed functionalization of aryl carbon-oxygen bonds in aromatic ethers with organoboron compounds.

The ruthenium-catalyzed reaction of aryl ethers having a carbonyl group at the ortho position to the ether group with organoboronates (R-B(OCH2CMe2CH2O), R = aryl, alkenyl, and alkyl) resulted in site-selective C-C bond formation. Among the transition metal complexes screened, the RuH2(CO)(PPh3)3 complex showed the highest activity. Several aromatic ketones having methoxy or phenoxy groups at the ortho position can also be used in this coupling reaction. A variety of arylboronates containing electron-donating (NMe2, OMe, methyl, and vinyl) and -withdrawing (F and CF3) groups reacted with methoxy ketones to give the corresponding coupling products in high yields.

Journal Article↗
PubMed2003

Ruthenium-catalyzed C-H/CO/Olefin coupling reaction of N-arylpyrazoles. Extraordinary reactivity of N-arylpyrazoles toward carbonylation at C-H bonds.

The reaction of 1-arylpyrazoles with CO and ethylene in the presence of Ru(3)(CO)(12) resulted in regioselective carbonylation at the ortho C-H bonds. While it is found that the pyrazole ring also functions as the directing group for C-H bond cleavage, the efficiency of the reaction depends on the position of the pyrazole ring.

Journal Article↗
PubMed2003

A GaCl3-catalyzed [4+1] cycloaddition of alpha,beta-unsaturated carbonyl compounds and isocyanides leading to unsaturated gamma-lactone derivatives.

A GaCl3-catalyzed reaction of alpha,beta-unsaturated ketones with isocyanides leading to the formation of unsaturated lactone derivatives is described. This is the first example of the catalytic [4+1] cycloaddition of alpha,beta-unsaturated ketones and isocyanides. GaCl3 is an excellent catalyst due to its lower oxophilicity, which is desirable for all of the key steps, such as E/Z isomerization, cyclization, and deattachment from the products.

Journal Article↗
PubMed2003

Ruthenium-catalyzed carbonylative cycloaddition of alpha-keto lactones with alkenes or alkynes: the participation of an ester-carbonyl group in cycloaddition reactions as the two-atom assembling unit.

The reaction of benzofuran-2,3-dione derivatives 1 with CO and alkenes (or alkynes) results in a carbonylative [2+2+1] cycloaddition in which the ester-carbonyl group is incorporated into a two-atom assembling unit to give spirolactone derivatives 2. This reaction provides the first example of an ester-carbonyl group participating in a carbonylative cycloaddition reaction.

Journal Article↗
PubMed2003

A ruthenium-catalyzed reaction of aromatic ketones with arylboronates: a new method for the arylation of aromatic compounds via C-H bond cleavage.

The ruthenium-catalyzed reaction of aromatic ketones with arylboronic acid esters (arylboronates) gave the ortho arylation product. For this coupling reaction, a RuH2(CO)(PPh3)3 complex exhibited the highest catalytic activity among the complexes screened. Several aromatic ketones, for example, acetophenones, acetonaphthone, alpha-tetralone, and benzosuberone, can be used in this coupling reaction. A variety of arylboronates containing electron-donating (OMe and NMe2) and -withdrawing (F and CF3) groups were found to react with aromatic ketones to give the corresponding aylation products. The corresponding arylboronic acids could be used in this coupling reaction, but the yields were slightly lower, as compared to those of the reaction using the corresponding arylboronates.

Journal Article↗
PubMed2002

Ru3(CO)12-catalyzed C-H/CO/olefin coupling of N-pyridylindolines. Direct carbonylation at a C-H bond delta to the pyridine nitrogen.

The reaction of N-pyridylindolines with CO and ethylene in the presence of Ru3(CO)12 results in direct carbonylation at a C-H bond delta to the pyridine sp2 nitrogen, which represents a new type of C-H/CO/olefin coupling. The presence of a pyridine ring as a directing group on the substrates is essential for the reaction to proceed. The choice of N,N-dimethylacetamide (DMA) as the solvent is crucial for the reaction to proceed efficiently.

Journal Article↗
PubMed2002

Ruthenium-catalyzed reaction of alpha,beta-unsaturated imines with carbon monoxide and alkenes leading to beta,gamma-unsaturated gamma-butyrolactams: involvement of direct carbonylation at olefinic C[bond]H Bonds as a key step.

The reaction of alpha,beta-unsaturated imines with CO and alkenes in the presence of Ru(3)(CO)(12) as a catalyst results in a three-component coupling reaction that gives alpha,alpha-disubstituted beta,gamma-unsaturated gamma-butyrolactams. The reaction proceeds via a two-step sequence involving the initial formation of ketone derivatives by catalytic carbonylation at the beta-olefinic C-H bonds of alpha,beta-unsaturated imines, followed by the (uncatalyzed) intramolecular nucleophilic attack of the imine nitrogen on the ketonic carbon to generate a tetrahedral intermediate, which then undergoes a 1,2-ethyl migration. The reaction of a cyclic unsaturated imine, derived from the reaction of (1R)-(-)-myrtenal with tert-butylamine, gives a beta-aminocyclopentene derivative, which is formed by an aldol-type condensation of the initially formed ketone, indicating the initial formation of ethyl ketone.

Journal Article↗
PubMed2002

Skeletal reorganization of enynes to 1-vinylcycloalkenes catalyzed by GaCl(3).

The skeletal reorganization of enynes is achieved by the presence of GaCl3 as the catalyst. This reaction demonstrates the first example of the skeletal reorganization of enynes catalyzed by typical metal complexes. The process is simple and provides a diverse range of enynes in good to high yields. The reaction of enynes bearing a monosubstituent at the terminal olefinic carbon proceeds in a stereospecific manner with respect to the geometry of the olefin moiety. Enynes, bearing two substituents at the olefinic terminal carbon, undergo an efficient skeletal reorganization, these substrates having been known to be unsuitable substrates for the skeletal reorganization of enynes.

Journal Article↗
PubMed2002

Catalytic C-h/olefin coupling.

The cleavage and addition of ortho C-H bonds in various aromatic compounds such as ketones, esters, imines, imidates, nitrile, and aldehydes to olefins and acetlylenes can be achieved catalytically with the aid of ruthenium catalysts. The reaction is generally highly efficient and useful in synthetic methods. The coordination to the metal center by a heteroatom in directing groups such as carbonyl and imino groups is the key. The reductive elimination to form a C-C bond is the rate-determining step.

Journal Article↗
PubMed1997

Ru(3)(CO)(12)-Catalyzed Reaction of Pyridylbenzenes with Carbon Monoxide and Olefins. Carbonylation at a C-H Bond in the Benzene Ring.

A ruthenium-catalyzed carbonylation at a C-H bond in a benzene ring is described. The reaction of pyridylbenzenes with CO (20 atm) and ethylene in toluene at 160 degrees C in the presence of a catalytic amount of Ru(3)(CO)(12) results in propionylation at an ortho C-H bond in the benzene ring. Carbonylation does not occur at the pyridine ring, although this is necessary as a directing group to promote the reaction. Olefins such as trimethylvinylsilane and tert-butylethylene in place of ethylene can also be used in this reaction, however 1-hexene, cyclohexene, allyltrimethylsilane, styrene, methyl methacrylate, vinyl acetate, triethoxyvinylsilane, and isopropenyltrimethylsilane do not afford the coupling products. Transition metal complexes, other than ruthenium carbonyl, examined thus far, do not show catalytic activity. In the reaction of meta-substituted pyridylbenzenes, such as those having Me, OMe, CF(3), and COOMe group at the meta position in the benzene ring, carbonylation takes place at the less hindered C-H bond exclusively, irrespective of the electronic nature of the substituents. It is apparent that steric factors are more important for the control of regioselectivity. The reaction is also applicable to naphthyl and thienyl rings. Six-membered heterocycles, such as 2-pyrimidine and 4-pyrimidine, are also effective directing groups for carbonylation at a C-H bond in the benzene ring. The present reaction represents the first, effective catalytic carbonylation reaction involving cleavage of the benzene C-H bond.

Journal Article↗