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59 KiB

Open AccessArticle

Alumina and Silica Oxides as Catalysts for the Oxidation of Benzoins to Benzils under Solvent-free Conditions

by N. Noroozi –Pesyan and A. H. Dabbagh

Molecules 2005, 10(11), 1364-1368; https://doi.org/10.3390/10111364 - 30 Nov 2005

Cited by 12 | Viewed by 7726

Alumina or silica gel are used as catalysts for a solvent-free oxidation of benzoins to the corresponding benzils. These catalysts are easily recovered after completion of the reactions, which are carried out either by heating in a sand bath or using microwave irradiation. [...] Read more.

Alumina or silica gel are used as catalysts for a solvent-free oxidation of benzoins to the corresponding benzils. These catalysts are easily recovered after completion of the reactions, which are carried out either by heating in a sand bath or using microwave irradiation. Comparison of the results obtained with both catalysts indicates that all the reactants examined were oxidized faster on alumina than on silica under these conditions. Full article

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64 KiB

Open AccessArticle

Synthesis and Bioactivity of New Phosphorylated R,R’-substituted Sulfoximines

by Monica Bellozas Reinhard and Susana Arnstein De Licastro

Molecules 2005, 10(11), 1369-1376; https://doi.org/10.3390/10111369 - 30 Nov 2005

Cited by 4 | Viewed by 9419

Abstract

R,R’-disubstituted sulfoximines were phosphorylated with O,O–diethylchlorophosphate and phosphorothionate to obtain new organophosphorus compounds. Afterpurification they were characterized by GC-MS and ¹H-NMR. The toxicity of thesynthesized O,O-diethyl N-(R,R’-disubstituted sulfoximine) phosphoro-amidothionateswas assayed on Musca domestica. It was found that the methyl phenyl derivative was [...] Read more.

R,R’-disubstituted sulfoximines were phosphorylated with O,O–diethylchlorophosphate and phosphorothionate to obtain new organophosphorus compounds. Afterpurification they were characterized by GC-MS and ¹H-NMR. The toxicity of thesynthesized O,O-diethyl N-(R,R’-disubstituted sulfoximine) phosphoro-amidothionateswas assayed on Musca domestica. It was found that the methyl phenyl derivative was themost toxic compound, followed by the dipropyl and dibutyl derivatives. The dihexylcompound was the less toxic of all the assayed compounds, being one hundred times lesstoxic than a paraoxon standard The anticholinesterasic activity of the correspondingphosphoramidates was assayed on homogenates of house flies’ heads, giving valuessimilar to paraoxon for the methyl phenyl derivative. Full article

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143 KiB

Open AccessArticle

Synthesis and Potent Antimicrobial Activity of Some Novel N-(Alkyl)-2-Phenyl-1H-Benzimidazole-5-Carboxamidines

by Hakan Göker, Mehmet Alp and Sulhiye Yıldız

Molecules 2005, 10(11), 1377-1386; https://doi.org/10.3390/10111377 - 30 Nov 2005

Cited by 50 | Viewed by 9171

Abstract

A series of 22 novel 1,2-disubstituted-1H-benzimidazole-N-alkylated-5- carboxamidine derivatives were synthesized and evaluated for in vitro antibacterial activity against S. aureus and methicillin resistant S. aureus (MRSA), E. coli, E. faecalis and for antifungal activity against C. albicans. Compound 59 [1-(2,4-dichlorobenzyl)-N- (2-diethylaminoethyl)-1H-benzimidazole-5-carboxamidine], with a [...] Read more.

A series of 22 novel 1,2-disubstituted-1H-benzimidazole-N-alkylated-5- carboxamidine derivatives were synthesized and evaluated for in vitro antibacterial activity against S. aureus and methicillin resistant S. aureus (MRSA), E. coli, E. faecalis and for antifungal activity against C. albicans. Compound 59 [1-(2,4-dichlorobenzyl)-N- (2-diethylaminoethyl)-1H-benzimidazole-5-carboxamidine], with a 3,4-dichlorophenyl group at the C-2 position, displayed the greatest activity (MIC = 3.12 μg/mL against both some bacteria and the fungus C. albicans). Full article

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96 KiB

Open AccessArticle

N,N’-Substituted 1,2,5 Thiadiazolidine 1,1-Dioxides: Synthesis, Selected Chemical and Spectral Proprieties and Antimicrobial Evaluation †

by A. Bendjeddou, R. Djeribi, Z. Regainia and N. Aouf

Molecules 2005, 10(11), 1387-1398; https://doi.org/10.3390/10111387 - 30 Nov 2005

Cited by 19 | Viewed by 7910

Abstract

The sulfamide functional group is increasingly relevant in both medicinal and bioorganic chemistry. We report here practical access to a series of N2,N5-substituted five-membered cyclosulfamides. The five-membered heterocyclic motif was prepared starting from proteogenic amino acids and chlorosulfonyl isocyanate via the Mitsunobu reaction. [...] Read more.

The sulfamide functional group is increasingly relevant in both medicinal and bioorganic chemistry. We report here practical access to a series of N2,N5-substituted five-membered cyclosulfamides. The five-membered heterocyclic motif was prepared starting from proteogenic amino acids and chlorosulfonyl isocyanate via the Mitsunobu reaction. Selected chemical and spectral proprieties and the antimicrobial evaluation of these compounds are detailed. Full article

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93 KiB

Open AccessArticle

Synthesis, Reactivity and Biological Activity of Novel Bisbenzofuran-2-yl-Methanone Derivatives

by Cumhur Kirilmis, Murat Koca, Alaaddin Cukurovali, Misir Ahmedzade and Cavit Kazaz

Molecules 2005, 10(11), 1399-1408; https://doi.org/10.3390/10111399 - 30 Nov 2005

Cited by 27 | Viewed by 7847

Abstract

Preparation of bisbenzofuran-2-yl-methanone (1), the corresponding ketoxime 4, semicarbazone and thiosemicarbazone 3a and 3b, ether derivatives of the ketoximes 5a-j and the alcohol 2 are described. These substances have been prepared in excellent yields. All the synthesized compounds except 5i have been tested [...] Read more.

Preparation of bisbenzofuran-2-yl-methanone (1), the corresponding ketoxime 4, semicarbazone and thiosemicarbazone 3a and 3b, ether derivatives of the ketoximes 5a-j and the alcohol 2 are described. These substances have been prepared in excellent yields. All the synthesized compounds except 5i have been tested against five different microorganisms and some of them were found to be active against some of the species studied. Full article

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119 KiB

Open AccessArticle

Facile Microwave-assisted Synthesis of 9,10-Dihydro-9,10-ethanoanthracene-11-carboxylic acid Methyl Ester

by Weerachai Phutdhawong and Duang Buddhasukh

Molecules 2005, 10(11), 1409-1412; https://doi.org/10.3390/10111409 - 30 Nov 2005

Cited by 8 | Viewed by 6639

Abstract

A facile, high yielding synthesis of 9,10-dihydro-9,10-ethano- anthracene-11- carboxylic acid methyl ester using a modified commercial domestic microwave oven is reported. Full article

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54 KiB

Open AccessArticle

Synthesis of 1-Methyl-3-oxo-7-oxabicyclo[2.2.1]hept-5-ene-2-carboxylic Acid Methyl Ester

by Valquiria Aragao, Mauricio Gomes Constantino, Adilson Beatriz and Gil Valdo José da Silva

Molecules 2005, 10(11), 1413-1418; https://doi.org/10.3390/10111413 - 30 Nov 2005

Cited by 6 | Viewed by 11756

Abstract

A simple and efficient method for the preparation of 1-methyl-3-oxo-7- oxabicyclo[2.2.1]hept-5-en-2-carboxylic acid methyl ester (1) is described. The first step is a highly regioselective Diels-Alder reaction between 2-methylfuran and methyl-3-bromo- propiolate. A remarkably difficult ketal hydrolysis reaction was effected by treatment with HCl, [...] Read more.

A simple and efficient method for the preparation of 1-methyl-3-oxo-7- oxabicyclo[2.2.1]hept-5-en-2-carboxylic acid methyl ester (1) is described. The first step is a highly regioselective Diels-Alder reaction between 2-methylfuran and methyl-3-bromo- propiolate. A remarkably difficult ketal hydrolysis reaction was effected by treatment with HCl, a simple reagent that was shown to be more efficient, in this case, than commonly used more elaborate methods. Full article

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97 KiB

Open AccessArticle

Reaction of Thallium(III) Salts with Homoallylic Alcohols: Ring Contraction vs. Dimethoxylation

by Luiz F. Silvia, Jr and Marcus V. Craveiro

Molecules 2005, 10(11), 1419-1428; https://doi.org/10.3390/10111419 - 30 Nov 2005

Cited by 7 | Viewed by 9028

Abstract

The oxidation of 2-(3,4-dihydronaphthalen-1-yl)-ethanol (1) with a variety ofthallium(III) salts was investigated. An indan, formed by a ring contraction reaction, wasobtained in good to moderate yields under a variety of reaction conditions: i) thalliumtriacetate (TTA) in aqueous AcOH; ii) thallium tris-trifluoroacetate (TTFA) in [...] Read more.

The oxidation of 2-(3,4-dihydronaphthalen-1-yl)-ethanol (1) with a variety ofthallium(III) salts was investigated. An indan, formed by a ring contraction reaction, wasobtained in good to moderate yields under a variety of reaction conditions: i) thalliumtriacetate (TTA) in aqueous AcOH; ii) thallium tris-trifluoroacetate (TTFA) in aqueousTFA; iii) TTFA in CH₂Cl₂; iv) thallium tripropionate (TTP) in aqueous propionic acidand v) thallium tris-[(S)-(-)-triacetoxypropionate] in aqueous (S)-(-)-2-acetoxypropionicacid. On the other hand, the reaction of compound 1 with TTA in methanol led to a 2:1mixture of the corresponding cis- and trans-dimethoxylated compounds, respectively.These compounds were formed by a thallium-promoted addition of methanol to thedouble bond. Full article

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Molecules, Volume 10, Issue 11 (November 2005) – 8 articles , Pages 1364-1428

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