巻号一覧
59 巻, 2 号
選択された号の論文の8件中1～8を表示しています
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侯 召民2001 年 59 巻 2 号 p. 82-91
発行日: 2001/02/01
公開日: 2009/11/13
ジャーナル フリーReactions of (C5Me5) 2Sm (THF) 2 with the potassium salts of monodentate anionic ligands ER (ER=OAr, SAr, NR1R2, etc.) yielded a series of C5Me5/ER-ligated samarium (II) complexes, which were stabilized by the neutral “C5Me5K” ligand. These complexes act as a unique catalytic system which can not only polymerize styrene and ethylene, but also copolymerize them into block styrene-ethylene copolymers under the presence of both monomers. Addition of an appropriate cocatalyst such as MMAO or AlR3/ [Ph3C] [B (C6F5) 4] to the samarocene complex (C5Me5) 2Sm (THF) 2 or (C5Me5) 2Sm (μ-Me) 2AlMe2 afforded a novel catalytic system for stereospecific 1, 4-cis living polymerization of butadiene and copolymerization of butadiene with styrene. The samarium (II) bis (aryloxide) complex Sm (OAr) 2 (THF) 3 showed an extremely high activity for ring-opening polymerization of ε-caprolactone and δ-valerolactone and copolymerization of ε-caprolactone with γ-butyrolactone.抄録全体を表示PDF形式でダウンロード (1531K) -
松田 冬彦2001 年 59 巻 2 号 p. 92-100
発行日: 2001/02/01
公開日: 2009/11/13
ジャーナル フリーThis review is intended to summarize the recent developments of the C-C bond formation reactions promoted by Sml2, with special emphasis placed on (1) the chelation-controlled reactions, (2) the tandem reactions, (3) the medium-ring annulation reactions, and (4) the new synthetic reactions for N-compounds.抄録全体を表示PDF形式でダウンロード (1358K) -
原田 俊郎, 奥 彬2001 年 59 巻 2 号 p. 101-108
発行日: 2001/02/01
公開日: 2009/11/13
ジャーナル フリー1-Alkynyl organometallics of main group metals have been frequently used as efficient carbon nucleophiles in organic syntheses. They react with a variety of electrophilic reagents generally at the carbon α to the metal atom. In order to develop a convergent method for the construction of complex carbon frameworks, a hitherto unexplored nucleophilic reactivity of alkynylmetals at the β position is investigated. The study reveals that various alkynylmetals react at the β position especially in intramolecular reactions. Alkynylzincates bearing a remote leaving group undergo smooth exo-cyclization at the β position with simultaneous 1, 2-migration of a ligand on the zinc atom to give 1- (cycloalkylidene) alkylzinc reagents, which can be used in subsequent reactions with electrophiles. Alkynylmetals of lithium, sodium, and potassium also undergo exo-cyclization to give cycloalkylidene carbene. A method for the synthesis of polycyclic compounds is developed utilizing the exo-cyclization of alkynylmetals and intramolecular C-H insertion of the resulting carbenes.抄録全体を表示PDF形式でダウンロード (1242K) -
佐治木 弘尚, 廣田 耕作2001 年 59 巻 2 号 p. 109-120
発行日: 2001/02/01
公開日: 2009/11/13
ジャーナル フリーThe chemoselective hydrogenation of an organic compound containing two or more reducible functional groups is a useful method in organic synthesis. We have found that a Pd/C catalyst formed an isolable complex with the ethylenediamine (en) employed as catalytic poison, and its complex catalyst [Pd/C (en)] chemoselectively hydrogenated a variety of reducible functionalities distinguishing O-benzyl, N-Cbz and O-TBDMS protective groups, benzyl alcohols and epoxides. The catalyst also regioselectively hydrogenolyzed 1, 2-epoxides to sec-alcohols depending upon the employed reaction conditions.抄録全体を表示PDF形式でダウンロード (1984K) -
上西 潤一, 河濱 令子2001 年 59 巻 2 号 p. 121-130
発行日: 2001/02/01
公開日: 2009/11/13
ジャーナル フリーA Z-alkenyl unit conjugated with an alkene or alkyne is often seen in structures of natural products. Since metal-, particularly Pd- or Ni- catalyzed cross-coupling reactions of alkenyl halide occur with high stereospecificity, the resulting alkenes are obtained with retention of the configuration of the starting alkenyl halide. To prepare geometrically pure polyenes and enynes bearing a conjugated Z-alkenyl group, geometrically pure (Z) -alkenyl halides are essentially required. This review describes stereoselective synthesis of (Z) -bromoalkenes and stereospecific synthesis of some natural polyenes having a Z-alkenyl unit, in the following order; i) stereoselective preparation of (1Z) -1-bromo-l-alkenes including alkynyl, alkenyl and aryl substituted bromoalkenes by Pd-catalyzed hydrogenolysis of 1, 1-dibromoalkenes with Bu3SnH, ii) Sonogashira, Suzuki, and Kumada-Tamao cross coupling reactions of (1Z) -1-bromo-l-alkenes with alkyne, alkenylboronic acid, and alkyl Grignard reagent in the presence of Pd or Ni catalysts, iii) the total synthesis of (2Z, 4E, 6E) -dehydrodendrolasin, (11Z) -retinal, and bombykol.抄録全体を表示PDF形式でダウンロード (1512K) -
山本 恵子, 増野 弘幸, 山田 幸子2001 年 59 巻 2 号 p. 131-141
発行日: 2001/02/01
公開日: 2009/11/13
ジャーナル フリーConformational analysis of the side chain of la, 25-dihydroxyvitamin D3 [1, 25- (OH) 2D3] and its 20-epimer revealed that the spatial region occupied by the side chain of these vitamin Ds can be divided to four areas. We designed and synthesized four diastereomers at C (20) and C (22) of 22-Me-1, 25- (OH) 2D3 whose side-chain mobility is restricted in one of these four areas. We evaluated biological activities of these four compounds. These studies allowed us to propose the relationship between the spatial region of vitamin D side-chain and the activity, an active space group concept. This concept has been generally accepted as explaining the three-dimensional structure and activity relationship of almost all known vitamin D analogs. To develop this concept to the concept including vitamin D receptor (VDR) protein, we constructed three-dimensional structure of the ligand binding domain (LBD) of the VDR by the homology modeling technique and docked 1, 25- (OH) 2D3 as a ligand into the constructed VDR-LBD.抄録全体を表示PDF形式でダウンロード (2040K) -
太田 光昭2001 年 59 巻 2 号 p. 142-149
発行日: 2001/02/01
公開日: 2009/11/13
ジャーナル フリーDesign, synthesis and pharmacophore modeling is described, on the basis of a medicinal chemistry research for a discovery of ramosetron hydrochloride as a novel serotonine (5-HT3) receptor antagonist, which has been launched as an effective agent for the treatment of nausea and vomiting associated with cancer chemotherapy.
Exploiting a new lead generation, a tetrahydrobenzimidazole derivative 11 was found from a various kind of fused imidazole derivatives. Optimization of compound 11 as racemates, followed by optical resolution, was accomplished to discover ramosetron as a potent, selective and optical active 5-HT3 receptor antagonist. Three-dimensional molecular modeling studies, based on a structure activity relationships, suggested that 'chiral selection' might be related to the conformationally restricted tetrahydrobenzimidazole ring, and a new pharmacophore model for the 5-HT3receptor antagonist was proposed. Further, preparation of a chiral degradation product as well as a metabolite of ramosetron was also achieved.抄録全体を表示PDF形式でダウンロード (1409K) -
侯 召民, 太田 光昭2001 年 59 巻 2 号 p. 150
発行日: 2001/02/01
公開日: 2009/11/13
ジャーナル フリーPDF形式でダウンロード (194K)
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