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p. 496-497
Received: 25 June 2006 / Published: 26 June 2006
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p. 498-513
Received: 12 June 2006; in revised form: 28 June 2006 / Accepted: 2 July 2006 / Published: 5 July 2006
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| Download PDF Full-text (118 KB) Abstract: Thioxothienopyrimidinones, alkylthio- and arylalkylthiothienopyrimidinones, thienopyrimidinones, thienopyrimidines a thienopyrimidinedione and a thienotriazolo- pyrimidinone were prepared from 2-amino-3-carboethoxy-4,5-disubstituted thiophenes and 2-amino-3-cyano-4,5-disubstituted thiophenes via reactions with different reagents.
p. 514-522
Received: 12 June 2006; in revised form: 9 July 2006 / Accepted: 12 July 2006 / Published: 14 July 2006
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| Download PDF Full-text (73 KB) Abstract: Some representative quinones, viz. one naphthoquinone (plumbagin) and five anthraquinones (alizarin, purpurin, chrysazin, emodin, and anthrarufin), were subjected to electrocoagulation. It was found that the rate and extent of coagulation of these compounds appears to correlate with the number and relative position of their phenolic substituent groups, and that all of the coagulated quinones could be recovered. Attempts were then made to electrochemically isolate three quinones, namely plumbagin, morindone and erythrolaccin, from natural sources.
p. 523-527
Received: 20 August 2005; in revised form: 10 March 2006 / Accepted: 12 March 2006 / Published: 14 July 2006
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| Download PDF Full-text (62 KB) Abstract: Reaction of various ketones with [hydroxy(tosyloxy)iodo]benzene (HTIB) followed by treatment of the α-tosyloxy ketones thus generated in situ with NaN3 offers a one-pot procedure for the synthesis of α-azido ketones. The HTIB used in this conversion may also be generated in situ by using iodosobenzene in combination with p-toluene- sulphonic acid.
p. 528-538
Received: 23 May 2006 / Accepted: 14 July 2006 / Published: 17 July 2006
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| Download PDF Full-text (384 KB) Abstract: Reaction of NaH with a THF solution of Eu(BTA)3(pypzH) [BTA = 1-benzoyl-3,3,3-trifluoroacetonate, pypzH = 2-(3-pyrazolyl)pyridine] leads to the formation of theeuropium-free tetrasodium complex [Na4 (pypzH)2 (μ4-BTA)2 (μ2-BTA)2 ]. Single-crystal X-ray diffraction studies revealed the presence of a centrosymmetric Na hybrid tetramer,which fully occupies the contents of the triclinic unit cell. The crystal structure containstwo individual Na cations, Na(1) and Na(2), which have highly irregular {NaN2 O3 } and{NaO6 } local coordination environments, respectively. One of the key features is thepresence of a central {Na4 O6 } core, which is unprecedented for Na . Externally to this{Na4 O6 } cluster pyrazolylpyridine organic molecules are N,N-chelated to Na(1). Eventhough all of the organic residues contain aromatic rings, the crystal packing of individualcentrosymmetric tetrasodium [Na4 (pypzH)2 (μ4-BTA)2 (μ2-BTA)2 ] molecular moieties isessentially driven through geometrical aspects combined with weak C–H···π interactions,rather than the expected a priori π-π interactions. The material also contains classicalstrong hydrogen bonds, even though these do not directly contribute to the packingdriving forces.
p. 539-548
Received: 16 June 2006; in revised form: 18 July 2006 / Accepted: 18 July 2006 / Published: 22 July 2006
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| Download PDF Full-text (119 KB) Abstract: A novel biosurfactant, 2-acyloxyethylphosphonate, was isolated from waterblooms of Aphanizomenon flos-aquae. Its structure was elucidated by chemical degradation and HRFABMS, GC/EI-MS and 1D- and 2D-NMR spectral analyses. The surfactant contained one mole of 2-hydroxyethylphosphonate and one mole of fatty acid, with hexadecanoic acid accounting for 84.1% of the total fatty acid content. The structure was confirmed by synthesis of 2-oleoyloxyethylphosphonate from ethylene oxide, phosphorus acid and oleic acid chloride. Considering the isolated surfactant molecule as hexadecanoyloxyethylphosphonic acid (mw. 364), the critical micelle concentration (CMC) was about 22 mM.
p. 549-555
Received: 1 June 2006; in revised form: 19 July 2006 / Accepted: 20 July 2006 / Published: 25 July 2006
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| Download PDF Full-text (62 KB) Abstract: The essential oil obtained by steam distillation of dried aerial parts of Ambrosia trifida L. from Northeast China was analyzed by GC and GC–MS. The essential oil yield based on dried plant material was 0.12% and thirty-five compounds (corresponding to 86.7% of the total weight) were identified. The main components were: bornyl acetate (15.5%), borneol (8.5%), caryophyllene oxide (8.3%), α-pinene (8.0%), germacrene D (6.3%), β-caryophyllene (4.6%), trans-carveol (2.9%), β-myrcene (2.6%), camphor (2.4%) and limonene (3.2%). A. trifida essential oil demonstrated bactericidal and fungicidal activity against six bacterial strains and two fungal strains, using the agar diffusion method.
p. 556-563
Received: 14 June 2006; in revised form: 22 July 2006 / Accepted: 24 July 2006 / Published: 26 July 2006
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| Download PDF Full-text (56 KB) Abstract: The acid-catalyzed cyclocondensation of N,N'-bisaryl (aryl = 2-pyrimidinyl, 2- pyrazinyl and 4-nitrophenyl) methanediamines 5a-c with aqueous formaldehyde in refluxing acetonitrile leads to the formation of the corresponding 1,3,5-triaryl-1,3,5-hexa- hydrotriazines 6a-c. The stoichiometric reactions of 2-aminopyrimidine and 2-amino- pyrazine with aqueous formaldehyde in acetonitrile under reflux conditions also afforded 6a and 6b, respectively. Treatment of 2-aminopyrimidine with aqueous formaldehyde in a 3:2 ratio yielded N,N',N"-tris(2-pyrimidinyl)dimethylenetriamine (7a) as a sole product, which upon subsequent reaction with formaldehyde also afforded 6a. The reaction of N,N'-biphenylmethanediamine with formaldehyde was also investigated.
p. 564-573
Received: 23 June 2006; in revised form: 20 July 2006 / Accepted: 21 July 2006 / Published: 26 July 2006
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| Download PDF Full-text (113 KB) Abstract: A stereoselective approach has been developed to the new sugar amino acid and potential potent turn mimic 5-O-(tert-butyldimethylsilyl)-3-deoxy-1,2-O- isopropylidene-3-methoxycarbonylamino-α-D-xylofuranose 3-C-carboxylic acid (12), via the [3,3]-sigmatropic rearrangement of allylic thiocyanates (Z)-6 and (E)-7, prepared from D-xylose. The synthesis of a new dipeptide 13 is also described.
p. 574-582
Received: 25 June 2006; in revised form: 12 July 2006 / Accepted: 13 July 2006 / Published: 27 July 2006
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| Download PDF Full-text (74 KB) Abstract: A series of novel 1-anilino-4-(arylsulfanylmethyl)phthalazines were designed and synthesized. The structures of all the compounds were confirmed by IR, 1H-NMR, elemental analysis and MS. The analogues 1-(3-chloro-4-fluoroanilino)-4-(3,4- difluorophenylthio-methyl)phthalazine (12) and 1-(4-fluoro-3-trifluoromethylanilino)-4- (3,4-difluorophenyl-thiomethyl)phthalazine (13) showed higher activity than a cisplatin control when tested in vitro against two different cancer cell lines using the microculture tetrazolium method (MTT) method.
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