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Volume 45, Issue 8
Displaying 1-10 of 10 articles from this issue
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Masato TANAKA1987 Volume 45 Issue 8 Pages 716-728
Published: August 01, 1987
Released on J-STAGE: January 22, 2010
JOURNAL FREE ACCESSExploitation of new methodologies for utilization of carbon monoxide is one of fundamental technologies for alternative chemical feedstocks at present as well as in the future. This article describes a personal perspective of the studies on carbon monoxide chemistry, and is divided into four items; 1) design of new catalyst systems for hydroformylation and its application to asymmetric carbonylation, 2) unsymmetrical ketone synthesis via carbonylative cross-coupling of halides, 3) synthesis of α-keto acid derivatives and α-hydroxy acids via double carbonylation of organic halides, and 4) direct carbonylation of hydrocarbons through C-H bond activation.View full abstractDownload PDF (1449K) -
Haruo SETO1987 Volume 45 Issue 8 Pages 729-744
Published: August 01, 1987
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSConsiderable advances in NMR spectroscopy made by the development of 2D NMR techniques in recent years have enabled easier structural determination of natural products in a short period without recourse to chemical manipulation. For example, the structure of the fungal product pereniporin could be established by the use of 2D long range C-H COSY, which was especially useful for connecting proton spin systems separated by a quaternary carbon or a heteroatom.
However, structural determination of very complicated natural products by 2D techniques has still remained as a difficult problem due, in part, to rapid transverse relaxation time (T2) of target molecules. For example, the structure of the antibiotic notonesomycin with 68 carbons has only been established by the use of a rather classical triple resonance.
The two more recently introduced techniques, HMBC (heteronuclear multiple bond correlation) and HOHAHA, have made possible to overcome such problems associated with T2 and are now very powerful tools for structural studies of complicated natural products. In particular, HMBC is useful for structural studies of natural products with many methyl groups such as polyketides and terpenes. Application of these techniques for structural elucidation of portimicin is described.View full abstractDownload PDF (1599K) -
Fumio TODA1987 Volume 45 Issue 8 Pages 745-754
Published: August 01, 1987
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSAlkaloids such as brucine and sparteine were shown to be useful for optical resolution of tertiary acetylenic alcohols, cyanohydrins, and secondary alcohols by a host-guest complex formation. Some chiral host compounds which are useful for optical resolution were designed by a simple idea, and the application of these to the resolution of a wide variety of organic guest compounds was reported.
In some cases of the optical resolution of guest compound by alkaloids or synthetic host compounds, racemic guest compound was converted into one optical isomer through a combination of its racemization and the complexation. In some cases, racemic host compounds were resolved by a complexation with optically active guest compound.
It was also reported that achiral amines such as DABCO, N, N'-dialkylpiperazine, and pyrazine are useful for optical resolution of a partially resolved alcohols by a complex formation of them.
It was also shorly reported that optically active host compound can be used for an enantioselective reaction of the guest compound included in it.View full abstractDownload PDF (1147K) -
Masaaki HIROBE1987 Volume 45 Issue 8 Pages 755-768
Published: August 01, 1987
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSNonheme iron-sulfur proteins are implicated as electron carriers in diverse processes of cell metabolism, and ferredoxins and rubredoxin form an important and comprehensive class of such proteins. The abilities of these proteins to act as electron carriers are related to their iron-sulfur active sites, which have several different oxidation levels interrelated by one electron transfer reactions. We have been attempting to develop novel and selective reductants for use in organic reactions. The iron-sulfur complexes are expected to be useful catalysts in organic reductions, because the abilities of the complexes as reductants are related to their redox potentials, which depend on the ligands, and the reactivities of the complexes should be easily controllable by replacement of the ligands. In this paper the catalytic activities of various synthetic iron-sulfur complexes in organic reactions are described.View full abstractDownload PDF (1385K) -
Kiyoshi IKEDA, Chikako SHIMIZU, Kazuo ACHIWA1987 Volume 45 Issue 8 Pages 769-783
Published: August 01, 1987
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSNew Methodology for efficient synthesis of biologically active site components of bacterial lipopolysaccharides, lipid A and the related compounds was developed. From novel key intermediates bearing chemically differentiated one amino and four hydroxyl groups or two amino and six hydroxyl groups, lipid X, Y, glucosamine-4-phosphoric acid derivatives and lipid As were synthesized. These chemically synthesized compounds possess interesting biological activities.View full abstractDownload PDF (1373K) -
Toshikazu HIRAO, Yoshiki OHSHIRO1987 Volume 45 Issue 8 Pages 784-791
Published: August 01, 1987
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSDialkyl phosphonate works as a reducing agent in the presence of triethylamine towards gem-dibromocyclopropanes and gem-dibromoolefins to give the corresponding monobromo derivatives, respectively. Reduction of gem-bromochlorocyclopropanes, 1, 1, 1-trichloromethane derivatives, 1, 1-dibromo-2-benzyloxyethylene, methyl α-bromocinnamate, α, p-dibromoacetophenone, and (1, 2-dibromoethyl) benzene is surveyed. Treatment of α-bromo- α, β-unsaturated carbonyl compounds or 1, 1-dibromo-2-trimethylsiloxycyclopropanes with dialkyl phosphonate and triethylamine affords, β, γ-unsaturated carbonyl compounds stereoselectively. This reductive deconjugation is applied to the syntheses of naturally occurring compounds, recifeiolide and pyrenophorin. Reductive phoshonation of gem-dibromocyclopropanes is performed by treatment with trialkyl phosphite-dialkyl phosphonate-triethylamine or trialkyl phosphite-triethylamine-water resulting in the formation of dialkyl cyclopropylphosphonates. The palladium-catalyzed reactions of aryl bromides or iodides with dialkyl phosphonates in the presence of triethylamine give the corresponding arylphosphonates. This method is extended to the stereospecific phosphonation of vinyl bromides.View full abstractDownload PDF (846K) -
Yoshio OKAMOTO, Eiji YASHIMA1987 Volume 45 Issue 8 Pages 792-804
Published: August 01, 1987
Released on J-STAGE: January 22, 2010
JOURNAL FREE ACCESSThree different types of asymmetric polymerizaitons of methacrylates have been achieved successfully. Racemic α-substituted benzyl methacrylates were polymerized with a high enantiomer-selectivity over 90% in the polymerization by (-) -sparteine-Grignard reagent complexes. Optically active polymethacrylates with nearly 100% one-handed helicity were obtained in the polymerization of such bulky esters as triphenylmethyl methacrylate with chiral anionic initiators. These chiral polymers were found to be very effective in separating the optical isomers under HPLC conditions. A very high enantiomer selection by the growing chain end with a stable helical structure was also attained in the polymerization of a bulky racemic monomer phenyl-2-pyridyl-ο-tolylmethyl methacrylate.View full abstractDownload PDF (1754K) -
Tatsushi SADO1987 Volume 45 Issue 8 Pages 805
Published: August 01, 1987
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESS -
Hiroyuki KURIHARA, Keiichi KIKUCHI, Kozo SHIRAI1987 Volume 45 Issue 8 Pages 806-808
Published: August 01, 1987
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSThe reaction of γ-thiobutyrolactone (A) with carbonohydrazide, thiocarbonohydrazide, carbonohydrazide imide or biguanide afforded 4- (4-mercaptobutyr amido) -3- (3-mercaptopropyl) -1H-1, 2, 4-triazole-5 (4H) -one, 4- (4-mercaptobutyr amido) -3- (3-mercaptopropyl) -1H-1, 2, 4-triazole-5 (4H) -thione, 3, 4-diamino-5- (3-mercaptopropyl) -4H-1, 2, 4-triazole, and 2, 6-diamino-4- (3-mercaptopropyl) -1, 3, 5-triazine in 60%, 36%, 93%, and 65% yields, respectively.
In the case of the reaction of A with carbonohydrazide, 1, 2-dihydro-6- (3-mercaptopropyl) -1, 2, 4, 5-tetrazine-3 (4H) -one was also obtained in 39%. Further, it was found that thus obtained thiols could be oxidized easily by the action of dimethyl sulfoxide to give corresponding disulfides.View full abstractDownload PDF (238K) -
[in Japanese], [in Japanese], [in Japanese], [in Japanese]1987 Volume 45 Issue 8 Pages 809
Published: August 01, 1987
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSDownload PDF (167K)
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