巻号一覧
48 巻, 6 号
選択された号の論文の18件中1～18を表示しています
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山田 順一, 山本 嘉則1990 年 48 巻 6 号 p. 436-446
発行日: 1990/06/01
公開日: 2010/01/22
ジャーナル フリーAcyclic stereocontrol is a pressing concern in modern organic synthesis. In recent years a number of methods have been developed for the stereocontrolled synthesis of acyclic compounds. We have found two new methods for acyclic stereocontrol via (1) Lewis acid promoted reactions and (2) an electron transfer process. (1) The reaction of group 14 organometallic compounds in the presence of Lewis acid proceeds with very high and novel stereoselectivities, which can not be realized by using ordinary carbanionic species themselves. (2) The opposite diastereoselectivity is observed between one electron transfer and two electron transfer process. For example, Michael nucleophilic addition of RCuLn to γ-chiral-α β-unsaturated esters produces the anti-adduct, while the electron transfer addition gives the syn-adduct.抄録全体を表示PDF形式でダウンロード (1079K) -
野依 良治, 岡田 茂満1990 年 48 巻 6 号 p. 447-456
発行日: 1990/06/01
公開日: 2009/11/13
ジャーナル フリーHomochiral or heterochiral interaction of enantiomers is a fundamental principle in crystal lattice formation, giving either racemates or conglomerates, and multi-stage interactions. Such diastereomeric effects arising from labile molecular assembly are also significant in various solution-phase phenomena related to physical, spectroscopic, and chromatographic properties of chiral organic substances. The enantiomer recognition also affects the degree of stereoselection and the efficiency of chiral multiplication in stereoselective organic reactions.抄録全体を表示PDF形式でダウンロード (1010K) -
玉尾 皓平1990 年 48 巻 6 号 p. 457-462
発行日: 1990/06/01
公開日: 2009/11/13
ジャーナル フリーThis review describes synthetic applications of “hypervalent”, “hypercoordinate” molecules of the Group 14 Group 17 elements, in which there is an expansion of the valence octet of the central atom. Reactions of penta- and hexa-coordinate silicon compounds are categorized into five types, and examples are presented to demonstrate (1) the activation of Si-C, Si-H, and Si-O bonds towards electrophiles, (2) the template effect through inclusion of an electrophilic center into the coordination sphere, and (3) some contrasting stereochemical outcomes. The following representative examples are also described : (4) stereocontrol via hypercoordinate Sn (IV) and Sn (II) species, (5) ligand coupling in triaryl derivatives of P (V) and S (VI), and (6) phenyl-Bi (V) and allyl-I (III) compounds as phenyl and allyl cation equivalents, respectively.抄録全体を表示PDF形式でダウンロード (613K) -
古賀 憲司1990 年 48 巻 6 号 p. 463-475
発行日: 1990/06/01
公開日: 2010/01/22
ジャーナル フリーLithium dialkylamides such as lithium diisopropylamide (LDA) are now used widely as bases of choice in synthetic organic chemistry. This article describes a relatively new area of asymmetric synthesis in which chiral lithium amide bases act both as bases and as chiral auxiliaries in the reactions to give optically active products enantioselectively. Examples of enantioselective deprotonation, enantioselective protonation, enantioselective carbon-carbon bond formation, and enantioselective dehydrohalogenation are reviewed. Since generation of carbanions by bases and their reactions constitute the backbone of organic synthesis, the chemistry presented here offers attractive opportunities for further developments.抄録全体を表示PDF形式でダウンロード (1318K) -
高橋 保1990 年 48 巻 6 号 p. 476-481
発行日: 1990/06/01
公開日: 2009/11/13
ジャーナル フリーCarbon-carbon bond activation of unstrained molecules using metal compounds were reviewed.
Novel transformations by carbon-carbon bond activation (i) - (iii) were proposed as targets.
(i) Regioselective substituent transfer.
(ii) Replacement of a carbon in the skeleton by other atoms.
(iii) Stereoselective recombination of a substituent.
Two transformations, (i) methyl group transfer from α-position to β-position and (ii) the replacement of a carbon by an oxygen atom, were shown using zircona and/or hafnacyclopentane derivatives in this article.抄録全体を表示PDF形式でダウンロード (592K) -
荒田 洋治, 長野 哲雄, 光本 篤史1990 年 48 巻 6 号 p. 482-493
発行日: 1990/06/01
公開日: 2009/11/13
ジャーナル フリーMonoclonal antibodies with catalytic activity have recently been generated and shown to carry out a variety of organic reactions, which include hydrolysis, lactonization, bimolecular amido bond formation, Claisen rearrangement, Diels-Alder reaction, elimination, photochemical and redox reactions. These antibodies, which are elicited by using natural products or synthetic compounds as haptens, possess high substrate specificity The catalytic acitvity of these antibodies is strongly inhibited by the haptens.
These new enzymelike catalysts were first prepared on the basis of the idea of the stabilization of transition state configurations on chemical pathways. Since the first successful attempt of the preparation of the catalytic antibody, a number of experimental data have been compiled in a short period of time and it has now become clear that the reduction of entropy in reactions, the introduction of adequate catalytic amino acid groups, and the incorporation of a variety of co-factors are also important factors in designing the catalytic antibody.
With the further progress in this field, many more interesting catalytic antibodies will be produced. It is also hoped that efforts in designing the antigen binding sites for the generation of new catalytic antibodies will be helpful in promoting a better understanding of the molecular mechanisms of antigen recognition and of a variety of chemical reactions in general.抄録全体を表示PDF形式でダウンロード (1321K) -
戸田 芙三夫1990 年 48 巻 6 号 p. 494-508
発行日: 1990/06/01
公開日: 2009/11/13
ジャーナル フリーIn expectation of designing new selective reaction centers, we prepared the host-guest inclusions in which molecular recognitions occur precisely and reactions of the guest proceed selectively in the solid state. Various simple orgainc compounds were found to include a wide variety of guest compounds, and not only photochemical but also usual organic reactions proceeded efficiently and selectively in the inclusion compounds in the solid state. We also found that inclusion complexation occurs in the solid state. Surprisingly, even enantioselective complexation occurred in the solid state.抄録全体を表示PDF形式でダウンロード (1684K) -
國枝 武久1990 年 48 巻 6 号 p. 509-516
発行日: 1990/06/01
公開日: 2010/01/22
ジャーナル フリーLiquid crystals possessing properties intermediate to crystals and isotropic liquids potentially serve as anisotropic reaction-media, in which the reactivities of a variety of reactions are expected to be considerably different from those in the liquid and the solid state. This article briefly surveys unimolecular and bimolecular photo- and thermal reactions conducted in thermotropic liquid crystals, of which unique features are distinctly reflected on the reaction rates, efficiencies and stereochemical courses. Structural compatibility and orientational restriction are generally suggested to play a major role in controlling the reactivities by such ordered media.抄録全体を表示PDF形式でダウンロード (867K) -
原田 明1990 年 48 巻 6 号 p. 517-521
発行日: 1990/06/01
公開日: 2009/11/13
ジャーナル フリーPhase-transfer catalysis has been extensively used to promote a variety of interfacial reactions. Most of the examples of this method involve transport of a reactant from the water phase into the organic phase where reactions take place. Recently, a new class of reactions involving transport of an organic-soluble reactant into an aqueous phase for reaction has been found. The recent reports describe a new example of this virtually unexplored method, which is named inverse phase-transfer catalysis (IPTC).抄録全体を表示PDF形式でダウンロード (521K) -
原田 馨1990 年 48 巻 6 号 p. 522-535
発行日: 1990/06/01
公開日: 2009/11/13
ジャーナル フリーThe plasmas generated by glow discharge, arc discharge and burning flame induce various organic reactions in aqueous solution, such as oxidation, dehydrogenation, carboxylation, amination, coupling reaction and fixation of nitrogen molecules etc. The main active species are considered to be hydroxyl and hydrogen radicals generated by the decomposition of water molecules under high energy conditions. The reactions induced by plasma are very strong processes without using any other chemical reagent. Considering the composition of the reaction products, the reactions proceed relatively controlled stepwise way. The new type of chemical reaction in aqueous solution induced by plasmas is an unusual reaction which could not be carried out by the conventional chemical ways, and is considered to have great potentialities in its application to many organic compounds in aqueous solution. These reactions are also interesting in connection with the abiotic formation of organic compounds during the course of chemical evolutional processes on the primitive Earth.抄録全体を表示PDF形式でダウンロード (1590K) -
真嶋 哲朗1990 年 48 巻 6 号 p. 536-547
発行日: 1990/06/01
公開日: 2009/11/13
ジャーナル フリーRecent studies of laser-induced organic synthesis (LIOS) are reviewed. This review describes :
1. introduction of LIOS,
2. characteristics of LIOS,
3. economics of LIOS,
4. LIOS by UV and visible lasers;
(a) medicine and related compounds,
(b) chemical products by radical chain-reactions,
(c) laser-induced catalytic reactions,
(d) addition reactions,
(e) asymmetric syntheses by circular polarized lasers,
5. LIOS by UV and visible lasers involving multiple-photon processes ;
(a) reactions in highly excited electronic states,
(b) reactions through multiphoton ionization,
(c) reactions of photochemical intermediates with high concentrations,
(d) reactions via laser ablation,
6. LIOS by a CO2 laser,
7. development of LIOS in the future.抄録全体を表示PDF形式でダウンロード (1298K) -
谷本 能文, 伊藤 道也1990 年 48 巻 6 号 p. 548-552
発行日: 1990/06/01
公開日: 2009/11/13
ジャーナル フリーA large number of chemical reactions in liquid solution can be regulated by magnetic fields. In radical reactions such as photoreaction of aromatic ketones in aqueous micellar solution, triplet-singlet intersystem crossing of a radical pair, a short-lived intermediate, is affected by magnetic fields (the radical pair mechanism). In electrochemical reactions, mass transportation from bulk solution to an electrode is influenced by magnetic fields (the magnetohydrodynamics mechanism).抄録全体を表示PDF形式でダウンロード (644K) -
硫黄, セレン, テルル化合物への電解還元法の可能性鳥居 滋1990 年 48 巻 6 号 p. 553-570
発行日: 1990/06/01
公開日: 2009/11/13
ジャーナル フリーThis review deals with recent aspects on electroreduction of sulfur, selenium, and tellurium compounds which involves three major topics as follows : (1) Characteristic features of electroreductive cleavages of S-S, Se-Se, Te-Te, S-N, S-C, and Se-C bonds ; (2) Electroreductive removal of sulfonyl protecting groups ; (3) Electrosyntheses of sulfur, selenium, and tellurium containing compounds which have interesting physical properties and novel functionalities.抄録全体を表示PDF形式でダウンロード (1760K) -
相澤 益男1990 年 48 巻 6 号 p. 571-576
発行日: 1990/06/01
公開日: 2009/11/13
ジャーナル フリーA new culture system has been developed for production of protein. Mammalian cells, MKN 45, were cultured on the surface of a potential-controlled electrode. Proliferation rate of cells depended on the electrode potential. In the potential range above 0 V vs. AgAgCl, proliferation rate markedly decreased with an increase in electrode potential. Such a potential dependency of proliferation was reversible without any fatal effects in the potential range from 0 to 0.4 V vs. AgAgCl. These findings have made it possible to electrically regulate proliferation rate.
Carcinoembryonic antigen (CEA) was produced by MKN 45 cells which were cultured on the surface of a potential-controlled electrode. The rate of CEA production was profoundly enhanced by a small potential application to the electrode. On the basis of these results an electrically controlled cell culture has been proposed.抄録全体を表示PDF形式でダウンロード (707K) -
大内 宗城, 河野 静江1990 年 48 巻 6 号 p. 577-586
発行日: 1990/06/01
公開日: 2010/01/22
ジャーナル フリーThree-dimensional (3D) NMR spectroscopy has been shown to be an effective method for resolving spectral overlap encountered in two-dimensional (2D) NMR experiments. We mainly explain heteronuclear three-dimensional experiments which are combinations of a heteronuclear shift correlation experiment with homonuclear 2D NMR experiments. Homonuclear 2D spectra (eg. DQF-COSY, HOHAHA) can be simplified with this technique by editing with respect to the heteronuclear chemical shift in a third-dimension. We introduce advantage, disadvantage and various practical aspects of three-dimensional NMR spectroscopies.抄録全体を表示PDF形式でダウンロード (1163K) -
詫摩 勇樹, 今木 直1990 年 48 巻 6 号 p. 587-592
発行日: 1990/06/01
公開日: 2010/01/22
ジャーナル フリーAutomatic laboratory reactor system has been developped and used for various organic synthesis. Heat flow studies follow the effects of external heating and cooling with time. Indeed automation significantly improves the efficiency of the researchers'work in number and in security, and moreover, will offer organic chemists a new tool for the organic chemical studies.抄録全体を表示PDF形式でダウンロード (624K) -
コンピューターの活用山田 晴夫, 土井 隆行, 高橋 孝志1990 年 48 巻 6 号 p. 593-605
発行日: 1990/06/01
公開日: 2009/11/13
ジャーナル フリーMolecular mechanics calculations and MM2 transition state models based on ab initio calculations have proven to be useful in predictions (or analyses) of stereoselectivities in organic reactions. Molecular modeling by means of these calculations can also be useful in designing synthetic key intermediates. This paper describes our recent works on molecular design based on molecular mechanics calculations which are directed toward the syntheses of steroid, germacrane lactones, periplanone-B, and neocarzinostatin chromophore using macrocyclically controlled reactions. Moreover, analyses of the stereoselectivities in the protonation of the cuprate-generated enolate are discussed. Programs for the generation of starting geometries for MM2 calculations and knowledge based systems for the organic synthesis such as SYNLIB, CAS, REACCS, CAMEO, and CHIRON are also discribed.抄録全体を表示PDF形式でダウンロード (1662K) -
野依 良治, 長野 哲雄, 真嶋 哲朗, 土井 隆行, 高橋 孝志1990 年 48 巻 6 号 p. 606
発行日: 1990/06/01
公開日: 2009/11/13
ジャーナル フリーPDF形式でダウンロード (158K)
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