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Molecules, Volume 11, Issue 4 (April 2006) – 10 articles , Pages 212-308

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79 KiB  
Correction
Publisher's Note added on 29 June 2006
by Shu-Kun Lin
Molecules 2006, 11(4), 232-241; https://doi.org/10.3390/11040232 - 29 Jun 2006
Cited by 6 | Viewed by 6144
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 [...] Read more.
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 Full article
115 KiB  
Article
Catalytic Properties of the Dioxomolybdenum Siloxide MoO2(OSiPh3)2 and its 2,2'-Bipyridine Adduct MoO2(OSiPh3)2(bpy)
by Sofia M. Bruno, Bernardo Monteiro, Maria Salete Balula, Catarina Lourenço, Anabela A. Valente, Martyn Pillinger, Paulo Ribeiro-Claro and Isabel S. Gonçalves
Molecules 2006, 11(4), 298-308; https://doi.org/10.3390/11040298 - 12 Apr 2006
Cited by 20 | Viewed by 9971
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 [...] Read more.
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 oC 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-1for 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. Full article
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66 KiB  
Article
Improved Synthesis of Substituted 6,7-Dihydroxy-4-quinazolineamines: Tandutinib, Erlotinib and Gefitinib
by Petr Knesl, Dirk Röseling and Ulrich Jordis
Molecules 2006, 11(4), 286-297; https://doi.org/10.3390/11040286 - 10 Apr 2006
Cited by 70 | Viewed by 16029
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. Full article
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58 KiB  
Article
Reactions of (Benzamidomethyl)triethylammonium Chloride with Some Inorganic Nucleophiles in Aqueous Media
by Emil Popovski, Jane Bogdanov, Metodija Najdoski and Evamarie Hey-Hawkins
Molecules 2006, 11(4), 279-285; https://doi.org/10.3390/11040279 - 10 Apr 2006
Cited by 5 | Viewed by 10601
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 [...] Read more.
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. Full article
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47 KiB  
Article
Microwave Assisted Synthesis of N-Arylheterocyclic Substituted-4-aminoquinazoline Derivatives
by Gang Liu, Song Yang, Baoan Song, Wei Xue, Deyu Hu, Linhong Jin and Ping Lu
Molecules 2006, 11(4), 272-278; https://doi.org/10.3390/11040272 - 10 Apr 2006
Cited by 23 | Viewed by 12315
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 [...] Read more.
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. Full article
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52 KiB  
Article
ZrOCl2·8H2O: An Efficient, Cheap and Reusable Catalyst for the Esterification of Acrylic Acid and Other Carboxylic Acids with Equimolar Amounts of Alcohols
by Hong-Bin Sun, Ruimao Hua and Yingwu Yin
Molecules 2006, 11(4), 263-271; https://doi.org/10.3390/11040263 - 10 Apr 2006
Cited by 38 | Viewed by 13480
Abstract
Esterifications of carboxylic acids with equimolar amount of alcohols could beefficiently catalyzed by ZrOCl2·8H2O. 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 [...] Read more.
Esterifications of carboxylic acids with equimolar amount of alcohols could beefficiently catalyzed by ZrOCl2·8H2O. 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 ZrOCl2·8H2O 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. Full article
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55 KiB  
Communication
Isolation and Biological Activity of New and Known Diterpenoids From Sideritis stricta Boiss. & Heldr.
by Turgut Kilic
Molecules 2006, 11(4), 257-262; https://doi.org/10.3390/11040257 - 29 Mar 2006
Cited by 33 | Viewed by 8416
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 [...] Read more.
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. Full article
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103 KiB  
Article
Substituted Pyrazinecarboxamides: Synthesis and Biological Evaluation
by Martin Dolezal, Lukas Palek, Jarmila Vinsova, Vladimir Buchta, Josef Jampilek and Katarina Kralova
Molecules 2006, 11(4), 242-256; https://doi.org/10.3390/11040242 - 29 Mar 2006
Cited by 60 | Viewed by 10504
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 [...] Read more.
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 H37Rv (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). Full article
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85 KiB  
Article
A Java Chemical Structure Editor Supporting the Modular Chemical Descriptor Language (MCDL)
by Sergei V. Trepalin, Alexander V. Yarkov, Igor V. Pletnev and Andrei A. Gakh
Molecules 2006, 11(4), 219-231; https://doi.org/10.3390/11040219 - 29 Mar 2006
Cited by 12 | Viewed by 17824
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 [...] Read more.
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). Full article
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215 KiB  
Article
2,6-Dichloro-9-thiabicyclo[3.3.1]nonane: Multigram Display of Azide and Cyanide Components on a Versatile Scaffold
by David Díaz Díaz, Antonella Converso, K. Barry Sharpless and M. G. Finn
Molecules 2006, 11(4), 212-218; https://doi.org/10.3390/11040212 - 27 Mar 2006
Cited by 15 | Viewed by 46614
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 [...] Read more.
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. Full article
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