Publications by authors named "Yuji Takashima"

The copper-catalyzed substitution reaction of diethyl phosphate derived from TMSCCCH(OH)CHCHOTBDPS with 3--CH-4-MeOCHMgBr, followed by several transformations, afforded a tumor necrosis factor inhibitor possessing a Ph-acetylene moiety. The inhibitor was also synthesized from phenylacetylene phosphate PhCCCH(OP(O)(OEt))CHCHOTBDPS. Furthermore, the substitution of phosphates derived from TMSCCCH(OH)CH and TMSCCCH(OH)--Pr with 3-F-4-PhCHMgBr gave the corresponding substitution products, which were transformed to flurbiprofen and its -Pr analogue, respectively.

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Transcatheter aortic valve implantation (TAVI) for patients with rheumatic aortic stenosis (AS) is not well-known. We herein report a case of TAVI in rheumatic AS without significant calcification and prior mitral valve replacement. An 80-year-old woman underwent TAVI for severe AS.

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From the chloroform extract of the fresh fruits of Diospyros maritima BLUME (Ebenaceae), five new naphthoquinone derivatives, 2,7'-dimethyl-2',3-bijuglone (27), 2,7'-dimethyl-3,3'-bijuglone (28), 2,7'-dimethyl-6,8'-bijuglone (29), 7,7'-dimethyl-3,3'-ethylidenebijuglone (30), and 2',7-dimethyl-3,6'-ethylidenebijuglone (31), were isolated, in addition to twenty-one known naphthoquinone derivatives: plumbagin (4), droserone (5), 2,3-epoxyplumbagin (8), 3,3'-biplumbagin (9), chitranone (10), 3,8'-biplumbagin (11), elliptinone (12), maritinone (13), isozeylanone (14), methylene-3,3'-biplumbagin (15), ethylidene-3,3'-biplumbagin (16), ethylidene-3,6'-biplumbagin (17), ethylidene-6,6'-biplumbagin (18), 7-methyl-β-dihydrojuglone (19), 7-methyljuglone (20), 2,3-epoxy-7-methyljuglone (21), neodiospyrin (22), mamegakinone (23), ehretione (24), isoxylospyrin (25) and β-dihydroplumbagin (26). The structures of the new compounds were established by spectral analysis. The quinones obtained from the chloroform extract of the fruits were compared with previously reported quinones obtained from ethanol extracts.

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Synthesis of (S)-imperanene (1) was studied by using copper-assisted allylic substitution of ArCH=CHCH(L)CH(2)Ar (L: leaving group) and (i-PrO)Me(2)SiCH(2)MgCl. Preliminary substitution between PhCH=CHCH(L)Me (L = AcO, PivO, MeOCO(2), (2-Py)CO(2)) and Bu copper reagents derived from BuMgX (X = Br, Cl) and CuBr.Me(2)S or CuCl in 1:1-40:1 ratios suggested acetate 28 as the best substrate.

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Four optically pure isomers of dioxetane (1) were decomposed by the action of the complex of an optically active crown ether with potassium tert-butoxide to afford light with lambda(max)CL and gave four different spectrum shapes.

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We have previously cloned the alternatively spliced isoform of fibroblast growth factor receptor 3 (FGFR3DeltaAB) that lacks the acid box in the extracellular region. To understand the biological functions and signal transduction of these FGFR3 isoforms, we analyzed the effect of FGF1 in ATDC5 cells, chondroprogenitor cell lines overexpressing these isoforms. In response to FGF1, FGFR3 induced a marked cell-morphology change to a round shape, while FGFR3DeltaAB did not.

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