Studies on 2-Aminothiophenes: Synthesis,Transformations, and Biological Evaluation of Functionally-Substituted Thiophenes and Their Fused Derivatives

Abstract

Heterocyclic enamines1 reacted with ethyl acetoacetate to afford the corresponding amide derivatives2. Treatment of2 with carbon disulphide yielded the dipotassium salts3which reacted in-situ with a variety of α -haloketones to give the respective substituted thiophenes5,8, and13. The reactivity of the latter products towards various chemical reagents was studied to yield their fused thiophene derivatives7,10,12, and14, respectively. Some representative compounds were tested for antimicrobial activity.     

An efficient and facile multicomponent synthesis of 4,6-diarylpyridine derivatives under solvent-free conditions

We present an efficient and facile synthesis of 4,6-diaryl-2-oxo-1,2-dihydropyridine-3-carbonitriles (5a–j) via a four-component system of aromatic aldehydes (1), acetophenones (2), ethyl cyanoacetate (3), and ammonium acetate (4). The short reaction time coupled with the simplicity of the reaction procedure and clean reaction make this method one of the most efficient methods for synthesis of this class of compounds.     

Preparation,Characterization and Electrochemical Behavior of Pd‐Au Alloy Incorporated into Zeolites/Graphite Electrodes

The present article reports the preparation of Pd‐Au alloy incorporated into NaY zeolites layer via simple immersion technique. Pd‐Au particles were incorporated into zeolites cages via Co‐impregnation or alternate impregnation of metal ions. Cyclic voltammetry was used to evaluate the state of the modified electrodes in alkaline media. Surface morphology as well as elemental composition of the modified layer were examined using Scanning electron microscopy (SEM) and energy dispersive X‐ray (EDX).     

Cycloaddition of Aroyl Isothiocyanate: A Novel Synthesis of Triazine,Oxazine, Pyrimidine,and Pyridine Derivatives

A simple and direct synthetic methodology for a novel series of azines and their annulated systems was performed. Heterocyclization of acyl isothiocyanate 2 with urea or malononitrile gave s‐triazine 4 and 1,3‐oxazine 7 derivatives, respectively. The reaction of heteroallene 1 with acetylacetone tolerated 2‐thioxopyridine derivative 9 . The latter compound underwent heterocyclization with urea, hydrazine hydrate, or phenyl hydrazine to give the annulated pyridines 10 – 12 . Pyrimidinethione 14 was resulted from reaction of acylisothiocyanate with enamine 13 . Condensation of compound 14 with hydrazine hydrate, phenyl hydrazine, urea, and 3‐nitrobenzaldehyde in the presence of ethyl cyanoacetate or sodium hydroxide afforded 15 – 20 , respectively.     

Synthesis and Anti-Inflammatory Activity of Some New Pyrimidinothienocinnoline Derivatives

Russian Journal of General Chemistry - Synthesis of a new series of pyrimidinothienocinnoline derivatives involves the reaction of 9-aminodibenzo[f,...     

New Approaches for the Synthesis of Thiazoles and Their Fused Derivatives with Antimicrobial Activities

The 2‐ethoxy carbonyl methylene thiazol‐4‐one ( 3 ) reacts with acetophenone ( 4 ) to give the ethyl 2‐(4‐oxo‐4,5‐dihydro‐thiazol‐2‐yl)‐3‐phenyl‐2‐butenoate ( 5 ). The reactivity of the latter product towards aromatic aldehydes 6a‐d , cyanomethylene reagents 9a,b , aromatic aldehydes 13a‐d , phenylisothiocyanate ( 16 ), elemental sulfur and aromatic amines ( 20a‐c ) was studied to give arylidene, pyridine, thiophene and anilide derivatives. Some of the newly synthesized derivatives were used to synthesize fused derivatives. The antimicrobial activities of the newly synthesized products were tested in vitro for antimicrobial activity against two bacterial isolates, one saprophytic (Escherichia coli) and the other parasitic (Xanthomonas citri) and for antifungal activity against one saprophytic (Aspergillus fumigatus) and two phytopathogenics (Rhizoctonia solani and Fusarium oxysporum).     

Synthesis and antiinflammatory activity of some pyrimidines and thienopyrimidines using 1-(2-Benzo[d][1,3]dioxol-5-yl)vinyl)-4-mercapto-6-methylpyrimidine-5-yl)ethan-2-one as a starting material

In continuation to our search for new heterocyclic systems based antiinflammatories, the suggestion and synthesis of some pyrimidines, thienopyrimidines, and their derivatives, were herein realized. The pharmacological screening showed that many of these compounds have good antiinflammatory activity. The structure assignments of the new compounds are based on chemical and spectroscopic evidence. The detailed synthesis, spectroscopic data, and pharmacological properties are reported. Correspondence: Abd El-Galil Elsayed Amr, National Research Center, Organic Chemistry Department, Cairo, Dokki, Egypt.     

Pyridazine derivatives and related compounds. 23*. Synthesis of 3-substituted pyrazolo[3,4-<Emphasis Type="Italic">c</Emphasis>]pyridazines and their application as disperse dyes

Acetylacetone and malononitrile were coupled with diazotized arylamines to give arylazoacetyl-acetones and arylazomalononitriles. When refluxed with 3-hydrazino-4,5-diphenyl-1H-pyrazolo-[3,4-c]pyridazine in the presence of ethanol/HCl, they yielded the corresponding 3-[4-(arylazo)-3,5-di-methylpyrazol-1-yl]- and 3-[3,5-diamino-4-(arylazo)pyrazol-1-yl]-4,5-diphenyl-1H-pyrazolo[3,4-c]pyri-dazine dyes. The dyes were applied to polyester and polyamide fabrics, and their spectral and fastness properties were measured.     

Reactivity of the Pt/WO3/GC Electrode Towards Ethylene Glycol Oxidation in 0.1 M H2SO4

WO₃ has been prepared via thermal decomposition of ammonium paratungstate. The obtained oxide has been characterized by X‐ray diffraction (XRD) spectroscopy. The particle size was found to increase with increasing calcination temperature. The modified Pt/WO₃/GC electrode has been prepared and characterized using various analytical and electrochemical techniques. The electrochemical oxidation of ethylene glycol (EG) on the modified electrode was investigated and compared with that of a Pt/GC electrode in acidic solution. The presence of WO₃ enhanced the electrode activity towards EG oxidation. The enhancement factor was found to depend on the ratio of WO₃:Pt as well as on the calcination temperature during WO₃ preparation