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Volume 60, Issue 10
Displaying 1-9 of 9 articles from this issue
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Tetsuo Ohta, Yohei Oe, Isao Furukawa2002 Volume 60 Issue 10 Pages 932-941
Published: 2002
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSα-Oxoketene O, N-acetals 1 act as nucleophiles and electrophiles, and are demonstrated as good starting materials for the preparation of various heterocyclic compounds. They are prepared from β-oxothiono esters 2, which are easily prepared from carbon disulfide, in only mixing with primary amine in the presence of triethylamine. Acetals 1 are converted to pyrrolidine-2, 5-diones 3, 1, 6-naphthyridine-2, 5 (1H, 6H) -diones 4, 1, 2, 3, 4-tetrahydro-2-pyridinones 5, piperidine-2, 6-diones 6, pyrroles 7, 2H-1, 3-oxazine-2, 4 (3H) -diones 8, and 4H-pyran-4-one 12 by the reaction with electrophiles. On the other hand, acetals 1 also react with nucleophiles to yield pyrazoles 19, isoxazoles 22, and pyrimidines 24. β-Oxothiono esters 2 are also good substrates for the preparation of 3-ethoxypyrazoles 25, 3-ethoxyisoxazoles 28, and 4-ethoxypyrimidines 29.View full abstractDownload PDF (1452K) -
Yasushi Tsuji, Makoto Tokunaga, Yasushi Obora2002 Volume 60 Issue 10 Pages 942-952
Published: 2002
Released on J-STAGE: January 22, 2010
JOURNAL FREE ACCESSRecent progress in supramolecular transition metal catalysis is descried. Various supramolecular catalyst systems containing cyclodextrins, dendrimers, calixarenes, and other moieties published in 1999-2002 are reviewed.View full abstractDownload PDF (1768K) -
Hisahiro Hagiwara2002 Volume 60 Issue 10 Pages 953-962
Published: 2002
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSUnmodified aldehydes directly add in 1, 4-manner to electron deficient olefins in the presence of a catalytic amount of diethylaminotrimethylsilane (DEATMS) in acetonitrile. Work up procedure was so simple that evacuation under reduced pressure followed by liquid chromatography or bulb to bulb distillation of the residue provided the products. Reaction of aldehydes with methyl α-haloacrylates generated in situ from methyl 2, 3-dihalopropanoates by DEATMS provided formylcyclopropanecarboxylates by domino conjugate addition-alkylation. Self- or cross-aldol con-densation of aldehydes afforded unsaturated aldehydes. The reaction was revealed to proceed via catalytic enamine pathway. The conjugate addition was also catalyzed by diethylamine or amine grafted on solid support in conventional organic solvent as well as ionic liquid, in which recycle of the solvent and the catalyst was realized.
Total syntheses of several bisabolane type sesquiterpenoids, (+) / (-) -a-bisabol-1-one, (-) - curcumene, (-) -curcuphenol, and (+) / (-) -elvirol have been accomplished starting from 5-ketoaldehydes prepared by 1, 4-conjugate addition of unmodified aldehydes to vinylketones employing citronellal as a chiral source.View full abstractDownload PDF (1514K) -
Hiroyuki Takemura2002 Volume 60 Issue 10 Pages 963-973
Published: 2002
Released on J-STAGE: January 22, 2010
JOURNAL FREE ACCESSC-F…M+ interaction was clearly shown by using fluorinated macrocyclic cage compounds. The interaction was proved by complexation studies, spectroscopic measurements (1H, 19F, 13C NMR), and X-ray crystallographic analyses. By the complexation, specific spectroscopic changes were observed. Especially, Cs+ and Tl+ complexes showed F…M+ spin couplings. In the crystal structure, short F…M+ contacts were observed, and C-F bond distances are elongated by the complexation. The C-F unit acts as an efficient donor in the complexes, which was proved by estimating bond valences (C-F…M+, O.-M+, and N.-M+) of the cations by Brown's equation. The nature of the C-F…M+ interaction was proved to be a cation-dipole interaction, and coordination bond is weak in this case.View full abstractDownload PDF (1906K) -
Kazuhiko Sato2002 Volume 60 Issue 10 Pages 974-982
Published: 2002
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSThe oxidation procedure must be high-yielding and with high selectivity without any by-products through a simple, safe operation using a clean, well-behaving, and cheap oxidant. Aqueous hydrogen peroxide is an ideal oxidant, because the atom efficiency is excellent and water is a sole theoretical side product. We here report the no-solvent oxidation using aqueous hydrogen peroxide under entirely halide-free conditions. A catalytic system consisting of sodium tungstate and methyltrioctylammonium hydrogensulfate effects oxidation of secondary alcohols to ketones and primary alcohols to carboxylic acids using 3-30% hydrogen peroxide without any organic solvents. The turnover number is two orders of magnitude higher than any previously reported hydrogen peroxide oxidation. Substituted benzyl alcohols are oxidized selectively to benzaldehydes and/or benzoic acids, depending on the property of the substituents. Addition of (aminomethyl) phosphonic acid accelerates epoxidation of olefins. These oxidation methods are high-yielding, clean, safe, operationally simple, and cost-effective and therefore meet with the requirements of contemporary organic synthesis. Cyclohexene is converted directly to analytically pure, crystalline adipic acid in an excellent yield. Sulfides are oxidized to sulfoxides or sulfones in high yield. Aldehydes are oxidized to carboxylic acids without affecting olefinic or alcoholic functions.View full abstractDownload PDF (1332K) -
Yutaka Kanda2002 Volume 60 Issue 10 Pages 983-988
Published: 2002
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSLeinamycin, a novel antitumor antibiotic, was isolated from a culture broth of Streptomyces sp. The unique structural features of leinamycin include the 1-oxo-1, 2-dithiolan-3-one moiety which is fused in a spiro fashion to an 18-membered lactam with an extensively conjugated thiazole ring. Leinamycin causes single strand scission of plasmid DNA in the presence of thiol cofactor. Isolation of a guanine-leinamycin adduct revealed the unprecedented chemical reactions which would be responsible for the thiol-mediated DNA cleavage by leinamycin. As a part of our program aimed at discovering clinically useful leinamycin derivatives, chemical modification of natural leinamycin have been investigated. In this review, synthesis and chemistry of novel leinamycin derivatives with potent antitumor activity are described. Thioester derivatives with 3-isothiazolidinone 1-oxide moiety are more stable than leinamycin and serve as prodrugs that could be converted into active form in biological media.View full abstractDownload PDF (816K) -
Jiro Tsuji2002 Volume 60 Issue 10 Pages 989-995
Published: 2002
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSNew methods of palladium-catalyzed facile arylation of malonates, ketones, aldehydes, esters, amides, and nitroalkanes, recently developed, are surveyed. Key of the reactions is selection of proper ligands and bases. Particularly, uses of bulky and electron-rich phosphines, such as tri-t-butylphoshine, are important.View full abstractDownload PDF (910K) -
Nobuyuki Nishino2002 Volume 60 Issue 10 Pages 996-998
Published: 2002
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESS -
[in Japanese], [in Japanese], [in Japanese]2002 Volume 60 Issue 10 Pages 999
Published: 2002
Released on J-STAGE: November 13, 2009
JOURNAL FREE ACCESSDownload PDF (218K)
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