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Displaying article 1-8
p. 902-912
Received: 14 September 2004 / Accepted: 4 October 2004 / Published: 30 November 2004
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| Download PDF Full-text (241 KB) Abstract: Cadmium carbonate was found to be a useful promoter in the Koenigs-Knorrsynthesis of 2-(4-methoxybenzyl)cyclohexyl-β-D-glycopyranosides. Using this promotermodel glucoside and galactoside derivatives of cyclic (i.e., secondary) alcohols weresynthesized in 50–60 % overall yields. Diastereoisomeric mixtures of products wereobtained in these syntheses, which started from racemic isomers of 2-(4-methoxy-benzyl)cyclohexanol. The prepared compounds have been purified and characterized bytheir 1 H- and 13 C-NMR spectra, as well as by their IR and MS spectra, in order to usethem as reference compounds in planned subsequent research.
p. 913-921
Received: 29 March 2004 / Accepted: 4 August 2004 / Published: 30 November 2004
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| Download PDF Full-text (216 KB) Abstract: Thirteen new triazoles containing 1,3-dioxolane rings were synthesized and their identities confirmed by means of IR, NMR, MS, elemental analysis and X-ray crystallography. The results of preliminary biological tests show that all of these compounds possess some fungicidal and plant growth regulant activities.
p. 922-938
Received: 5 March 2004 / Accepted: 24 June 2004 / Published: 30 November 2004
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| Download PDF Full-text (247 KB) Abstract: The alkylation of β-dicarbonyl compounds in a K2 CO3 /DMSO system wasfound to afford O- and C-alkylated derivatives, depending on the type of the β-dicarbonylcompound involved. The alkyl derivatives obtained were used in the synthesis of some newspiro barbituric acid derivatives. Quantum chemical calculations were carried out toelucidate the reaction mechanisms for some typical synthesis.
p. 939-948
Received: 24 September 2004 / Accepted: 31 August 2004 / Published: 30 November 2004
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| Download PDF Full-text (214 KB) Abstract: Reaction of the amino acid D-phenylalanine ethyl ester (4) with cinnamaldehyde gave chiral Schiff base 5, which underwent an asymmetric Staudinger [2+2] cycloaddition reaction with phthalimidoacetyl chloride to give the monocyclic β-lactam 6 as a single stereoisomer. Ozonolysis of 6 followed by reduction with lithium aluminum tri(tert-butoxy) hydride afforded the hydroxymethyl β-lactam 8. Treatment of 8 with methansulfonyl chloride gave the mesylated monocyclic β-lactam 9, which was converted to the bicyclic β-lactam 10 upon treatment with 1,8-diazabicyclo[5,4.0] undec- 7-ene (DBU). Deprotection of the phthalimido group in β-lactams 6 and 10 by methylhydrazine and subsequent acylation of the free amino β-lactams with different acyl chlorides in the presence of pyridine afforded mono and bicyclic β-lactams 14a-d and 15a-d respectively. The compounds prepared were tested against Escherichia coli, Staphilococcus citrus, Klebsiella pneumanie and Bacillus subtillis. Some of these compounds showed potential antimicrobial activities.
p. 949-956
Received: 10 March 2004 / Accepted: 30 August 2004 / Published: 30 November 2004
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| Download PDF Full-text (444 KB) Abstract: Two mononuclear complexes, [Ni(acac)2]·0.5CH3 OH (1) and[Co(acac)2 NO3 ]·2H2 O (2) (acac = pentane-2,4-dione), have been synthesized andcharacterized by single crystal X-ray analysis. Complex 1 crystallizes in the monoclinicspace group P21/c with a = 9.295(4), b = 11.450(5), c = 12.974(6) å, V = 1379.1(11) å3 ,β = 92.854(7), and Z = 4. Complex 2 crystallizes in the triclinic space group P(-1) with a= 8.153(9), b = 9.925(11), c = 10.355(12), V = 746.3(15) å3 , α = 70.530(16), β =71.154(15), γ = 80.698(16) and Z = 2. Complex 1 has a one-dimensional chain-likestructure, which is extended by weak hydrogen contacts, while complex 2 shows a three–dimensional network structure.
p. 957-967
Received: 13 July 2004 / Accepted: 9 September 2004 / Published: 30 November 2004
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| Download PDF Full-text (194 KB) Abstract: New 1,2,3-thiadiazole and 1,2,3-selenadiazole derivatives, 14-23, were prepared from the ketones 1-5 via the corresponding semicarbazones or hydrazones 6-12. The Hurd-Mori and Lalezari methods were used, respectively, for the preparation of these 1,2,3-thiadiazole and 1,2,3-selenadiazole derivatives. The intermediate 13 was also trapped, separated and fully characterized. These derivatives are important for photocrosslinking processes and due to their potential biological activity.
p. 968-977
Received: 12 July 2004 / Accepted: 6 September 2004 / Published: 30 November 2004
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| Download PDF Full-text (231 KB) Abstract: The polycondensation of tetrahydrofuran with maleic anhydride catalyzed byMaghnite-H+ (Mag-H) was investigated. Maghnite is a montmorillonite sheet silicateclay that is exchanged with protons to produce Maghnite-H [1]. It was found that thepolymerization in bulk is initiated by Mag-H in the presence of acetic anhydride at 40°C.The effects of the amounts of Mag-H and acetic anhydride were studied. Thepolymerization yield increased as the proportions of catalyst and acetic anhydride wereincreased.
p. 978-987
Received: 7 July 2004 / Accepted: 1 August 2004 / Published: 30 November 2004
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| Download PDF Full-text (255 KB) Abstract: The sex-based differences between the effects of two novel sugar-based drug candidates, a sulfated polymannuroguluronate (SPMG-911) and an acidic oligosaccharide sugar chain compound (AOSC-971), on the enzymes CYP 1A2 and CYP 2E1 were investigated. The results showed that neither SPMG-911 nor AOSC-971 have any effect on CYP1A2, while AOSC-971 induced the CYP 2E1 in male rats. The results are useful for their safety evaluation, as well as for the prediction of inter-drug interactions associated with the two drugs.
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