Molecules

88 KiB

Open AccessArticle

Microwave-Assisted Synthesis of Some 3,5-Arylated 2-Pyrazolines

by Davood Azarifar and Hassan Ghasemnejad

Molecules 2003, 8(8), 642-648; https://doi.org/10.3390/80800642 - 31 Jul 2003

Cited by 82 | Viewed by 10020

Condensation of 2-acetylnaphthalene with benzaldehydes under microwave irradiation affords chalcones which undergo facile and clean cyclizations with hydrazines RNHNH₂ (R= H, Ph, Ac) to afford 3,5-arylated 2-pyrazolines in quantitative yields, also under microwave irradiation and in the presence of dry AcOH as cyclizing agent. The results obtained indicate that, unlike classical heating, microwave irradiation results in higher yields, shorter reaction times (2-12 min.) and cleaner reactions. Full article

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208 KiB

Open AccessArticle

Syntheses of New Unsymmetrical and Symmetrical Diarylsulphides and Diarylsulphones Containing Thiazolinyl and Thiazolidinonyl Moieties Using 4,4'-Diacetyldiphenylsulphide

by M. A. Abbady, Sh. H. Abdel-Hafez, M. M. Kandeel and M. I. Abdel-Monem

Molecules 2003, 8(8), 622-641; https://doi.org/10.3390/80800622 - 31 Jul 2003

Cited by 12 | Viewed by 11326

Abstract

Condensation of 4,4’-diacetyldiphenyl sulphide (2) with variable amounts of thiosemicarbazide (3) in refluxing ethanol and in the presence of catalytic amounts of dry piperidine afforded only 4-acetylthiosemicarbazone-4’-acetyldiphenyl sulphide (5). Condensation of 2 with excess semicarbazide hydrochloride (4) in the presence of fused sodium acetate and/or piperidine yielded 4,4’-diacetylsemicarbazone diphenyl sulphide (6), whereas use of equimolar amounts of 2 and 4 afforded 4-acetyl-semicarbazone-4’-acetyldiphenyl sulphide (7). 4-Acetylsemicarbazone-4’-acetylthiosemicarbazone diphenyl sulphide (8) was also obtained via two different routes. The effect of tautomeric structure 5d is discussed. 4-(4"-phenyl-Δ³-thiazoline-2"-acetylazino)-4’-acetyldiphenyl sulphide (9), 4-(5"-carboxyethyl-4"-thiazolidinone-2"-acetylazino)-4’-acetyldiphenyl sulphide (10), 4-(4"-thiazolidinone-2’-acetylazino)-4’-acetyldiphenyl sulphide (11) and 4-(4"-methyl-Δ³-thiazoline-2"-acetylazino)-4’-acetyldiphenyl sulphide (12) were prepared by interaction of 5 with phenacylbromide, bromodiethylmalonate, chloro ethylacetate and chloroacetone, respectively. Sulphides 9-12 were easily condensed with 3 to afford the corresponding 4-(heterocyclic moiety-2"-acetylazino)-4’-acetylthiosemicarbazone diphenyl sulphides 23-26. Oxidation of the prepared sulphides 5-7, 9-12, 23 and 25-26 using H₂O₂/glacial AcOH mixtures yielded only 4,4’-diacetyldiphenyl sulphone (13) as the main product in every case, besides 3 and 4 in certain cases. Unsymmetrical and symmetrical sulphones 14-22 were obtained starting from 13. The structures of the synthesized compounds are based on IR, ¹H-NMR, ¹³C-NMR and mass spectral data. A theoretical study on some of the prepared compounds using molecular modeling was carried out. Full article

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134 KiB

Open AccessArticle

Constituents from Moghat, the Roots of Glossostemon bruguieri (Desf.)

by Meselhy R. Meselhy

Molecules 2003, 8(8), 614-621; https://doi.org/10.3390/80800614 - 31 Jul 2003

Cited by 51 | Viewed by 14374

Abstract

The new biflavone moghatin (3″′-hydroxycupressuflavone) was isolated from Moghat, the dried peeled roots of Glossostemon bruguieri (Desf.), together with five known compounds: 4′-methoxyisoscutellargin, sesamin, chrysophanol, emodin and methoxyemodin (physcion). The structures of these compounds were assigned on the basis of spectroscopic data. Occurrence [...] Read more.

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62 KiB

Open AccessArticle

A Facile Procedure for the Generation of Dichlorocarbene from the Reaction of Carbon Tetrachloride and Magnesium using Ultrasonic Irradiation

by Haixia Lin, Mingfa Yang, Peigang Huang and Weiguo Cao

Molecules 2003, 8(8), 608-613; https://doi.org/10.3390/80800608 - 31 Jul 2003

Cited by 8 | Viewed by 10505

Abstract

An improved method for the generation of dichlorocarbene was developed that utilizes ultrasound in the reaction of carbon tetrachloride with magnesium. High yields of gem-dichlorocyclopropane derivatives can be obtained in the presence of olefins by this method. Full article

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8 KiB

Open AccessCorrection

Peter Karuso and Paul J. Scheuer, Natural Products from Three Nudibranchs: Nembrotha kubaryana, Hypselodoris infucata and Chromodoris petechialis, Molecules, 2002, 7, 1-6

by Peter Karuso

Molecules 2003, 8(8), 607; https://doi.org/10.3390/80800607 - 31 Jan 2002

Viewed by 6464

Abstract

n/a Full article

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Molecules, Volume 8, Issue 8 (August 2003) – 5 articles , Pages 607-648

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