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Volume 49, Issue 12
Displaying 1-8 of 8 articles from this issue
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Atsutaka KUNAI, Sotaro ITO, Kazuo SASAKI1991 Volume 49 Issue 12 Pages 1100-1109
Published: December 01, 1991
Released on J-STAGE: November 16, 2009
JOURNAL FREE ACCESSActivation of dioxygen and selective oxidation of aromatic substrates with use of reducing gas/electron-transfer catalyst have been examined. A catalyst system composed of Pd and Cu species operates in various reaction media, such as water, benzene, and acetic acid, and affords oxygenated products selectively in high yields. Under strongly acidic conditions, monohydroxylated compounds are produced as the main products, while dihydroxylated compounds become predominant under less acidic conditions. A catalyst system including Pd species alone shows similar activity, but main products are always monohydroxylated compounds. Characteristic aspects of these catalyst systems have been discussed.View full abstractDownload PDF (1276K) -
Kazuo YAMAGUCHI1991 Volume 49 Issue 12 Pages 1110-1118
Published: December 01, 1991
Released on J-STAGE: January 28, 2010
JOURNAL FREE ACCESSω-Hydroxy carboxylic acids bearing 2-8 ether oxygens and aromatic rings and the ω-methoxy and ω-benzyloxy derivatives were synthesized as analogues of natural carboxylic ionophores. These compounds were employed as carriers for active and competitive transport of alkali and alkaline earth metal ions through 1, 2-dichloroethane or 1-hexanol as an organic liquid membrane. Effect of hydrophobic groups, number of ether oxygens, and terminal hydroxy group of the synthetic ionophores on the ion transport ability and selectivity was investigated. Among the ionophores, one compound bearing 8 ether oxygens and 5 aromatic rings exhibited K+ selectivity over Na+ comparable to natural ionophores. Crystal structures of potassium, rubidium, and cesium salts of the compound were determined by X-ray diffraction and the conformations in solution were analyzed by NMR spectroscopy.View full abstractDownload PDF (1119K) -
Hiroshi IWANE, Takahiro SUGAWARA, Makoto IMANARI1991 Volume 49 Issue 12 Pages 1119-1126
Published: December 01, 1991
Released on J-STAGE: November 16, 2009
JOURNAL FREE ACCESS4, 4'-Biphenol derivatives are very useful for the raw material of polyesters, polycarbonates, polysulfones and polyepoxides. Many manufacturing process have been investigated. In this review, we describe especially recent progress in manufacturing process for two representatives.
(1) Some manufacturing process for the 4, 4'-biphenol;phenol process, 2, 6-di-t-butylphenol process, 4-halophenol process, 4, 4'-diisopropylbiphenyl process, 4, 4'-dihalobiphenyl process, alkaline fusion process and 4-hydroxycyclohexanone process.
(2) Our new process for the 3, 3', 5, 5'-tetramethyl-4, 4'-biphenol.View full abstractDownload PDF (915K) -
Masakazu MURATA, Hirosato EBIIKE, Kazuo ACHIWA1991 Volume 49 Issue 12 Pages 1127-1141
Published: December 01, 1991
Released on J-STAGE: November 16, 2009
JOURNAL FREE ACCESSNew strategy of lipase-catalyzed asymmetric reactions is described. Chiral 2-O-substituted glycerols, 2-substituted 1, 3-propanediols and 1, 4-diols were obtained in high optical yields by the asymmetric transesterification using activated esters as acyl donors. Facile process for the kinetic resolution of racemic alcohols was developed by the lipase-catalyzed esterification with acid anhydride. And chiral 1, 4-dihydropyridines and barbiturates were obtained in high optical yields by the lipase-catalyzed hydrolysis of their acyloxymethyl groups. Chiral medicines were synthesized from optically active compounds obtained by these lipase-catalayzed asymmetric reactions.View full abstractDownload PDF (1469K) -
Hiromichi TANAKA, Hiroyuki HAYAKAWA, Tadashi MIYASAKA1991 Volume 49 Issue 12 Pages 1142-1155
Published: December 01, 1991
Released on J-STAGE: November 16, 2009
JOURNAL FREE ACCESSLithiation of nucleosides has been shown to be a highly general method for chemical modification of the base moiety. A wide range of substitutions can be accomplished simply by using different electrophiles in the reaction with the respective lithiated species.
In the case of uridine, the protecting group of the sugar hydroxyl groups appeared to be an important determinant of the efficiency and regiochemical outcome of the lithiation. Regiospecific abstraction of H-6 in uracil moiety with LDA takes place only when 2'- and 3'-hydroxyl groups are simultaneously protected with an alkylidene group, e.g. isopropylidene group. Subsequent reaction with a variety of electrophiles furnishes 6-substituted derivatives, which are difficult to synthesize by any other methods.
As an application of the C-6 lithiation with LDA, a series of 6-iodo and 6-phenylthio acyclouridines were synthesized. Among these derivatives, 1- [(2-hydroxyethoxy) methyl] -6-phenylthiothymine (HEPT) was found to be a new lead for anti-HIV agents. The activity of HEPT is highly specific to HIV-1 : other viruses, including HIV-2, are totally non-susceptible to HEPT. Further synthetic study improved the activity to a greater extent. In terms of excellent activity, low toxicity, and effectiveness against AZT-resistant HIV-1, these HEPT analogues constitute promising candidates for AIDS chemotherapy.View full abstractDownload PDF (1507K) -
Yoshihisa MIZUNO1991 Volume 49 Issue 12 Pages 1156-1161
Published: December 01, 1991
Released on J-STAGE: January 28, 2010
JOURNAL FREE ACCESSDownload PDF (769K) -
Masamichi MARUTA1991 Volume 49 Issue 12 Pages 1162-1163
Published: December 01, 1991
Released on J-STAGE: November 16, 2009
JOURNAL FREE ACCESS -
[in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...1991 Volume 49 Issue 12 Pages 1164
Published: December 01, 1991
Released on J-STAGE: November 16, 2009
JOURNAL FREE ACCESSDownload PDF (175K)
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