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p. 212-218
Received: 16 March 2006 / Accepted: 27 March 2006 / Published: 27 March 2006
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| Download PDF Full-text (215 KB) Abstract: 2,6-Dichloro-9-thiabicyclo[3.3.1]nonane, easily available by an improved condensation of sulfur dichloride, sulfuryl chloride, and 1,5-cyclooctadiene, is a well- behaved scaffold for the nucleophilic substitution of azides and cyanides via neighboring- group participation by the sulfur atom. The products are isolated in high yields with purity >95% by simple extraction and washing protocols.
p. 219-231
Received: 7 December 2005; in revised form: 24 March 2006 / Accepted: 24 March 2006 / Published: 29 March 2006
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| Download PDF Full-text (85 KB) Abstract: A compact Modular Chemical Descriptor Language (MCDL) chemical structure editor (Java applet) is described. The small size (approximately 200 KB) of the applet allows its use to display and edit chemical structures in various Internet applications. The editor supports the MCDL format, in which structures are presented in compact canonical form and is capable of restoring bond orders as well as of managing atom and bond drawing overlap. A small database of cage and large cyclic fragment is used for optimal representation of difficult-to-draw molecules. The improved algorithm of the structure diagram generation can be used for other chemical notations that lack atomic coordinates (SMILES, InChI).
p. 232-241
Published: 29 June 2006
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| Download PDF Full-text (84 KB) Abstract: There is a pagination error in this paper. The page number for the first page (Sergei V. Trepalin et al. Molecules 2006, 11 , 219) is assigned correctly. However, the following pages were not correctly paginated and the final page number should be 231 instead of 241. The original file is still provided. Pages 232-241 are thus taken as blank pages. We apologize for this error and for any inconvenience
p. 242-256
Received: 20 July 2005; in revised form: 19 March 2006 / Accepted: 20 March 2006 / Published: 29 March 2006
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| Download PDF Full-text (103 KB) Abstract: Condensation of the corresponding chlorides of some substituted pyrazine-2-carboxylic acids (pyrazine-2-carboxylic acid, 6-chloropyrazine-2-carboxylic acid, 5-tert-butylpyrazine-2-carboxylic acid or 5-tert-butyl-6-chloropyrazine-2-carboxylic acid) withvarious ring-substituted aminothiazoles or anilines yielded a series of amides. Thesyntheses, analytical and spectroscopic data of thirty newly prepared compounds arepresented. Structure-activity relationships between the chemical structures and the anti-mycobacterial, antifungal and photosynthesis-inhibiting activity of the evaluatedcompounds are discussed. 3,5-Bromo-4-hydroxyphenyl derivatives of substitutedpyrazinecarboxylic acid, 16-18, have shown the highest activity against Mycobacteriumtuberculosis H37 Rv (54-72% inhibition). The highest antifungal effect againstTrichophyton mentagrophytes, the most susceptible fungal strain tested, was found for5-tert-butyl-6-chloro-N-(4-methyl-1,3-thiazol-2-yl)pyrazine-2-carboxamide (8, MIC =31.25 μmol·mL-1 ). The most active inhibitors of oxygen evolution rate in spinachMolecules 2006, 11 243 chloroplasts were the compounds 5-tert-butyl-6-chloro-N-(5-bromo-2-hydroxyphenyl)- pyrazine-2-carboxamide (27, IC50 = 41.9 μmol·L-1 ) and 5-tert-butyl-6-chloro-N-(1,3- thiazol-2-yl)-pyrazine-2-carboxamide (4, IC50 = 49.5 μmol·L-1 ).
p. 257-262
Received: 28 October 2005; in revised form: 20 February 2006 / Accepted: 21 February 2006 / Published: 29 March 2006
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| Download PDF Full-text (55 KB) Abstract: Nine known and one new ent-kaurene diterpenoid were isolated from the acetone extract of Sideritis stricta Boiss & Heldr. The new compound, identified as ent-1β-hydroxy-7α-acetyl-15β,16β-epoxykaurane (1) by IR, 1D and 2D NMR techniques and mass spectra, was isolated along with sideroxol (2), 7-acetyl sideroxol (3), 7-epicandicandiol (4), linearol (5), ent-7α,15β,18-trihydroxy-kaur-16-ene (6), ent-7α-acetyl,15,18-dihydroxy-kaur-16-ene (7), foliol (8), sideridiol (9) and siderol (10). The antibacterial and antifungal activities of these compounds and the whole crude acetone extract were evaluated against E. coli, S. aureus, K. pneumeonia and C. albicans.
p. 263-271
Received: 20 January 2006 / Accepted: 9 April 2006 / Published: 10 April 2006
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| Download PDF Full-text (52 KB) Abstract: Esterifications of carboxylic acids with equimolar amount of alcohols could beefficiently catalyzed by ZrOCl2 ·8H2 O. Acrylate esters were obtained in good yields undersolvent-free conditions at ambient temperature. The esterification of other carboxylicacids with alcohols also proceeded at ambient temperature or at 50 oC to afford esters inhigh yields. If the esterification was performed in toluene under azeotropic refluxconditions to remove water, both the catalytic activity of ZrOCl2 ·8H2 O and the rate ofesterification could be increased greatly. Furthermore, in the present catalytic system, theesters could be easily separated from the reaction mixtures and the catalyst could beeasily recovered and reused.
p. 272-278
Received: 16 January 2006; in revised form: 25 March 2006 / Accepted: 7 April 2006 / Published: 10 April 2006
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| Download PDF Full-text (47 KB) Abstract: A simple, efficient, and general method has been developed for the synthesis of various N-aryl heterocylic substituted-4-aminoquinazoline compounds from 4-chloro- quinazoline and aryl heterocyclic amines under microwave irradiation using 2-propanol as solvent. The advantages of the use of microwave irradiation in relation to the classical method were demonstrated.
p. 279-285
Received: 3 March 2006 / Accepted: 9 April 2006 / Published: 10 April 2006
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| Download PDF Full-text (58 KB) Abstract: A variety of benzamidomethyl derivatives were prepared in water under alkaline conditions (pH>9) via reaction of (benzamidomethyl)triethylammonium chloride (1) with different inorganic nucleophiles. Reaction of 1 with hydroxylamine did not give the expected mono(benzamidomethyl)-hydroxylamine (3) but rather gave N,N- di(benzamidomethyl)hydroxylamine (2). Reactions of 1 with sodium azide and potassium cyanide gave benzamidomethyl azide (4a) and benzamidomethyl cyanide (4b) respectively. Potassium thiocyanate and sodium iodide reacted with 1, and the anion- exchanged products (benzamidomethyl)triethylammonium isothiocyanate (5a) and (benzamidomethyl)triethylammonium iodide (5b) were thus obtained. Cyanamide and potassium cyanate reacted readily with 1 and both gave the same mixture of di(benzamidomethyl)amine (7) and tri(benzamidomethyl)amine (8). All the reactions occurred smoothly, under mild conditions, to give the products in moderate to high yields.
p. 286-297
Received: 9 March 2006 / Accepted: 10 April 2006 / Published: 10 April 2006
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| Download PDF Full-text (66 KB) Abstract: The synthesis of three substituted 6,7-dihydroxy-4-quinazolineamines: tandutinib (1), erlotinib (2) and gefitinib (3) in improved yields is reported. The intermediates were characterized by NMR and the purities determined by HPLC.
p. 298-308
Received: 31 March 2006; in revised form: 10 April 2006 / Accepted: 10 April 2006 / Published: 12 April 2006
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| Download PDF Full-text (115 KB) Abstract: The tetrahedral triphenylsiloxy complex MoO2 (OSiPh3 )2 (1) and its Lewis baseadduct with 2,2'-bipyridine, MoO2 (OSiPh3 )2 (bpy) (2), were prepared and characterised byIR/Raman spectroscopy, and thermogravimetric analysis. Both compounds catalyse theepoxidation of cis-cyclooctene at 55 o C using tert-butylhydroperoxide (t-BuOOH) isdecane as the oxidant, giving 1,2-epoxycyclooctane as the only product. The best resultswere obtained in the absence of a co-solvent (other than the decane) or in the presence of1,2-dichloroethane, while much lower activities were obtained when hexane oracetonitrile were added. With no co-solvent, catalyst 1 (initial activity 272 mol·molMo-1 ·h-1 for a catalyst:substrate: oxidant molar ratio of 1:100:150) is much more active than 2(initial activity 12 mol·molMo–1 ·h–1 ). The initial reaction rates showed first orderdependence with respect to the initial concentration of olefin. With respect to the initialamount of oxidant, the rate order dependence for 1 (1.9) was higher than that for 2 (1.6).The dependence of the initial reaction rate on reaction temperature and initial amount ofcatalyst was also studied for both catalysts. The lower apparent activation energy of 1 (11kcal·mol–1 ) as compared with 2 (20 kcal·mol–1 ) is in accordance with the higher activity ofthe former.
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