Synthesis and Antimicrobial Activity of Some New 5-(3-Chloro-1-Benzothiophen-2-YL)-1,3,4-Oxadiazole-2-Thiol and Their Derivatives

Abstract

3-Chloro-1-benzothiophene-2-carbonylchloride 1 was made to reacts with hydrazine hydrate afforded 3-chloro-1-benothiophene-2-carbohydrazide 2 in good yield. 5-(3-chloro-1-benzothiophen-2-yl)-1,3,4-oxadiazole-2-thiol 4 was synthesized from 3-chloro-1-benzothiophene-2-carbohydrazide 2. Mannich bases, alkyl halide, and acid chlorides derivatives were then prepared. Compound 4 on condensation with chloroacetone in the presence of NaOH as base and ethanol as solvent gave 1-{[5-(3-chloro-1-benzo[b]thiophen-2-yl)-1,3,4-oxadiazol-2-yl]sulfanyl}propan-2-on 6. Condensation of compound 6 with various aromatic aldehydes afforded a series of chalcones 7a–h. The structures of all the synthesized compounds were confirmed by spectral data and have been screened for antibacterial activity.

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Investigation on the Ring-Opening Reactions of 3-(1H-1,2,4-Triazol-1-yl)1,5-benzothiazepines with Arylonitrile Oxides

Abstract

Novel ring opening compounds, (Z)-2-((Z)-((E)-1,3-diaryl-2-(1H-1,2,4-triazol-1-yl)allylidene)amino)aryl N-hydroxybenzimidothioates 4a–r, were obtained from the reaction of 2,4-diaryl-3-(1H-1,2,4-triazol-1-yl)-2,5-dihydro-1,5-benzothiazepines 3a–f and arylonitrile oxides. The structure of these products has been elucidated by spectroscopic analysis and, in one case, X-ray crystallographic analysis. According to the result, it was presumed that this reaction did not proceeded through 1,3-dipolar cycloaddition reaction.

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Efficient,Stereoselective Approach to the Synthesis of 3-(1-Phenyl-2-(Z-styrylsulfonyl)-1H-imidazol-4-yl)-2H-chromen-2-ones

Reaction of phenyl acetylene with 3-(1-aryl-2-mercapto-4-imidazolyl)-2H-1-benzopyran-2-ones (4) in the presence of sodium hydroxide in absolute ethanol led to the formation of 3-(1-phenyl-2-(Z-styrylthio)-1H-imidazol-4-yl)-2H-chromen-2-ones (6) in excellent yields. These, on further oxidation with H₂O₂/AcOH, gave the corresponding sulfones (7) with retention of stereochemistry.

Reaction of Red Phosphorus with 4-Methoxystyrene in KOH-DMSO System: One-Pot Synthesis of Tris[2-(4-methoxyphenyl)ethyl]phosphane Oxide

Abstract

Red phosphorus reacts with 4-methoxystyrene in the KOH-DMSO superbase system (130 °C, 3 h, Ar) in the presence of a small quantity of H₂O to give tris[2-(4-methoxyphenyl)ethyl]phosphane oxide as the main product in 30% yield. Microwave activation of the reaction (600 W, 6 min) affords basically a mixture of the phosphane oxide and tris[2-(4-methoxyphenyl)ethyl]phosphane (in a ratio of 1:1). When the mixture is exposed to air (r.t., 24 h), the phosphane oxide is formed in 85% yield.

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One-Pot Green Synthesis of 3'-(2-Aminobenzimidazolyl)-2-Phenyl Spiro[4H-Benzopyran-4,2'-Thiazolidin]-4-Ones and Acylation Using Trifluoroacetic Anhydride

Abstract

An expeditious one-pot synthesis of a novel heterocyclic system, 3′-(2-aminobenzimidazolyl)-2-phenyl spiro[4H-benzopyran-4,2′-thiazolidin]-4-ones, has been accomplished by condensing substituted hydrazinobenzimidazole, flavanone, and mercaptoacetic acid by conventional heating in ethanol or toluene, and in an ionic liquid, viz., 1-butyl-3-methyl-imidazolium hexafluorophosphate. Excellent yields (85%–90%) and higher purity are obtained in the ionic-liquid-mediated synthesis as compared with the conventional procedure (55%–60%). Further, these compounds were acylated with trifluoroacetic anhydride. The structures of the compounds were confirmed by IR, ¹H NMR, ¹³C NMR, mass spectral data, and elemental analysis. The compounds, upon evaluation for their antibacterial, antifungal, and insecticidal activities, exhibited excellent results.

[Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements for the following free supplemental resource: Table S1, S2, and S3]

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Synthesis and Herbicidal Activity of O,O-Dialkyl(phenyl)-N-{1-[(6-chloropyridin-3-yl)methyl]-4-cyano-1H-1,2,3-triazol-5-yl}-1-amino-1-substitutedbenzyl-phosphonates

Abstract

A series of novel α-amino phosphonate derivatives containing both pyridine and 1,2,3-triazole moieties 4 were synthesized via a multi-step reaction. First, the condensation of 5-amino-1-[(6-chloropyridin-3-yl) methyl]-4-cyano-1H-1,2,3-triazole with various aromatic aldehydes in the presence of magnesium perchlorate afforded imines 3 in moderate yields; second, imines 3 reacted with dialkyl phosphites or triphenyl phosphite to give the title compounds 4 in moderate to good yields. Their structures were elucidated by spectroscopic data (IR, ¹H NMR, ³¹P NMR, ESI-MS) and elemental analysis. The preliminary bioassay (in vitro) indicated that some of the title compounds 4 possessed moderate herbicidal activities against dicotyledonous plants (Brassica campestris L) at a concentration of 100 mg/L. However, compounds 4 did not exhibit herbicidal activities against Brassica campestris L at a concentration of 10 mg/L.

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Reaction of 1-Aryl-1H-1,2,3-Triazole-4-Carbonyl Chlorides/Isothiocyanates with 3-Amino-5-Methylisoxazole

Abstract

1-Aryl-1H-1,2,3-triazole-4-carbonyl chlorides were selected as starting materials for the Boulton–Katritzky rearrangement. When 3-amino-5-methylisoxazole was acylated by 1-aryl-1H-1,2,3-triazole-4-carbonyl chlorides, 1-aryl-5-methyl-N-(5-methylisoxazol-3-yl)-1H-1,2,3-triazole-4-carboxamides 5 were obtained and no further rearrangement occurred. On the other hand, when 1-aryl-1H-1,2,3-triazole-4-carbonyl chlorides were first converted into isothiocyanates by the reaction with KSCN and then were allowed to react with 3-amino-5-methylisoxazole 4 in one pot, intermediate thioureas were formed and spontaneously transformed in statu nascendi into 1,2,4-thiadiazole derivatives 6.

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Synthesis,Dimeric Crystal Structure,and Fungicidal Activity of 1-(4-Methylphenyl)-2-(5-((3,5-dimethyl-1H-pyrazol-1-yl)methyl)-4-phenyl-4H-1,2,4-triazol-3-ylthio)ethanone

Abstract

A new triazole compound, C₄₆H₄₆N₁₀O₂S₂, has been synthesized, and the crystal structure was determined by a single crystal X-ray diffraction study. The fungicidal activity of the title compound was determined, and the results showed that it displays moderate fungicidal activity.

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One-Pot Synthesis of Novel Rhodanine Based Ketenimines Via Multicomponent Reactions

Abstract

Synthesis of polyfunctionalized ketenimines via three-component reactions of rhodanine and 5-(4-dimethylaminobenzylidene)-rhodanine with dialkyl acetylenedicarboxylates and alkyl isocyanides is described. The reactions proceed smoothly under mild conditions leading to the desired products in good yields. In the case of methyl acetylenecarboxylate, the reaction led to methyl (Z)-3-({5-[(E)-1-(tert-butylamino)methylidene]-4-oxo-4,5-dihydro-1,3-thiazol-2-yl}sulfanyl)-2-propenoate in low yield.

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Symthesis of 3-[1-(p-Fluorophemyl)-Pyrazol-3-YL]-Quimoxalimomes

Abstract

3-[1-(p-Fluorophenylhydrazono)-L-threo-2,3,4-tri hydroxybutyl1-2-quinoxalinowe was prepared and trarrsformed to 3-[5-acetoxymetnyl-1-(p-fluorophenyl)-pyrazol-3-yl]-2-quinoxalinone. N-methylation, followed oy dehydrative cyclisation, gave the M-methyl-derivative of the latter pyrazole. Periodate oxidation gave a glyoxalyl derivative whose aldehyde functionality was confirmed by reduction and oximation.     

Synthesis,Characterization, and Biological Screening of Some Novel Thiazolidin-4-One and α-Aminophosphonate Derivatives

Abstract

Synthesis of some new functionalized thiazolidin-4-ones and α-amino phosphonate derivatives has been reported. The imines were synthesized from the reaction of various substituted anilines with 1-phenyl-3-(pyridine-4-yl)-1H-pyrazole-4-carbaldehyde in ethanol at reflux condition. The corresponding thiazolidin-4-ones and α-aminophosphonates were prepared by reaction of imines with mercaptoacetic acid and triethyl phosphite, respectively. The structures of the newly synthesized compounds were confirmed by IR, ¹H NMR, and mass spectral data and were evaluated for their antimicrobial activities.

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On the Reactivity of Metal and Organometallic Halides and Pseudohalides Towards Stannosiloxane (Ph3Sn-O-SiPh3)

Abstract

Interactions of HgX₂ (X = Cl, Br, I, SCN, CN, NCO), SbCl₃, TeCl₄, and PhTeCl₃ with Ph₃Sn-O-SiPh₃ at room temperature have been found to proceed with the simultaneous cleavage of Sn-O and Si-O bonds, invariably yielding Ph₂SnO, Ph₃SiX, and the corresponding organo-mercury, -antimony, and -tellurium derivatives. The course of the reactions suggests the instability of the Sn-O-M (M = Hg, Sb, Te) system.

GRAPHICAL ABSTRACT