Green synthesis of Fe3O4/ZnO magnetic core-shell nanoparticles by Petasites hybridus rhizome water extract and their application for the synthesis of pyran derivatives: Investigation of antioxidant and antimicrobial activity

In this research, Fe₃O₄/ZnO magnetic core-shell nanoparticles (Fe₃O₄/ZnO MCNPs) were synthesized through a green method using Petasites hybridus rhizome water extract as a reducing and stabilizing agent. The morphology and size of the Fe₃O₄/ZnO MCNPs was identified by X-ray diffraction, scanning electron microscopy, and Energy-dispersive X-ray spectroscopy (EDX) analysis. The catalytic activity of the Fe₃O₄/ZnO MCNPs was evaluated in the efficient and green preparation of pyran derivatives in excellent yield using three-component reactions of dimedone, aldehydes, and malononitrile in ethanol at room temperature. The ability of some synthesized compounds to scavenge the 2,2-diphenyl-1-picrylhydrazyl radical was measured and the results proved this observation. Moreover, the antimicrobial activity of some synthesized compounds was proved by employing the disk diffusion test on Gram-positive and Gram-negative bacteria. The results for the disk diffusion test showed that compounds ( 4c, 4d, 4f and 4g ) prevented bacterial growth.     

Efficient access to 2-aryl-3-substituted benzo[b]thiophenes

[reaction: see text] Benzo[b]thiophene derivatives are important in part because of their use as selective estrogen receptor modulators. They are usually synthesized by intramolecular cyclization. Here, we propose a method for the synthesis of 2-arylbenzo[b]thiophenes with heteroatoms at the 3-positions directly from the benzo[b]thiophene core by using an aromatic nucleophilic substitution reaction and Heck-type coupling. This methodology provides 2-aryl-3-amino or phenoxybenzo[b]thiophenes in about 35% overall yield in 5 steps.     

Exploration of quinoxaline derivatives as antimicrobial and anticancer agents

Novel 2 and 3‐substituted quinoxaline derivatives were synthesized through various synthetic pathways, among which cyanoacetamide and cyanoacetohydrazide quinoxaline derivatives 4a‐c and 11a‐c , respectively, were synthesized. Furthermore, methoxy quinoxaline derivatives 3c and quinoxaline derivatives bearing substituted pyridines 6a,b , 12a,b , and 13a,b were designed to be synthesized. However, we have synthesized acrylohydrazide 5a,b and 7 /acrylamide derivatives, Schiff base analogues 14a‐f , pyrazole derivatives 15a‐e, amide derivatives 16a‐f , guanidine derivatives 16 g,h as well as, quinoxalin‐2‐methylallyl propionate derivative 14g . All the synthesized compounds were confirmed via spectral data and elemental analyses. Moreover, the newly synthesized compounds were evaluated for their antimicrobial activity (Gm +ve, Gm ?ve in comparison to Gentamycin a standard) and fungi (in comparison to Ketoconazole as a standard). Thus, compound 16b showed promising antimicrobial activity against B. subtilis, P. vulgaris, and S. mutants with values ranging from 20 to 27‐mm zone of inhibition. While compounds 5a , 14e,f, and 16a,c,d,g,h showed potent antimicrobial activity. Moreover, the National Cancer Institute (NCI) selected 20 compounds that were submitted for anticancer screening against 60 types of cancer cell lines. The most active compounds are 5b and 12a where compound 5b containing 2,4‐dichlorophenyl moiety at cyanoacetamide linkage of hydrazine quinoxaline backbone exerted significant growth inhibition activity against Leukemia MOLT‐4, Renal cancer UO‐31, and Breast cancer MCF‐7. In addition, compound 12a having 4,6‐diaminopyridinone side chain at position‐3 of quinoxaline nucleus exhibited remarkable anticancer activity against renal cancer UO‐31.     

2D ZnO/Fe3O4 nanocomposites as a novel catalyst-promoted green synthesis of novel quinazoline phosphonate derivatives

In this research a novel and efficient procedure for the preparation of phosphonate derivatives using the reaction of 2,4-dihydroxyacetophenone, isopropenylacetylene, 2-amino-N-alkyl benzamide, dialkyl acetylenedicarboxylates and trimethyl phosphite or triphenyl phosphite in the presence of reusable 2D ZnO/Fe₃O₄ nanocomposites in water at room temperature was investigated. The 2D ZnO/Fe₃O₄ nanocomposites were synthesized using ionic liquid [OMIM]Br as a stabilizer and soft template. In addition, the power of antioxidant for some prepared compounds was studied using trapping of radicals by DPPH and a ferric reduction activity potential experiment. As a result, compound 6f displayed a noteworthy power for trapping of free radicals and 6b exhibited excellent reducing power compared with standards (BHT and TBHQ). Moreover, the antimicrobial power of some prepared quinazolinone phosphonates was proved by employing the disk diffusion experiment on two kinds of bacteria, Gram-positive and -negative bacteria. The obtained outcomes of disk diffusion test showed that these compounds prevented bacterial growth. Some advantages of this procedure are: short time of reaction, high yields of product and easy separation of catalyst and products.     

Synthesis and Antimicrobial Activity of Some Novel Substituted Bis‐Pyridone,Pyrazole, and Thiazole Derivatives

A variety of novel bis‐heterocyclic derivatives were synthesized via the reaction of bis‐cyanoacetanilide derivative 3 with various aromatic aldehydes (1:2 molar ratio), to give the corresponding bis‐arylidene derivatives 5a , 5b , 5c , 5d , 5e , 5f , 5g , 5h , 5i , 5j , 5k , 5l , 5m . On the other hand, reacting compound 3 with substituted 2‐hydroxybenzaldehydes 6a , 6b , 6c afforded 2‐iminochromene‐3‐carboxamides 7a , 7b , 7c . The reaction of compound 5 with malononitrile afforded the novel bis‐pyridones 9a , 9b , 9c , 9f , 9g , 9h . The reaction of 5 with hydrazine derivatives afforded pyrazoles 11a , 11b , 11c , 11d , 11e , 11f , respectively. Compound 3 reacts with phenyl isothiocyanate in the presence of potassium hydroxide at room temperature followed by addition of some different halo‐carbonyl compounds to afford bis‐poly‐functionalized thiazole derivatives 13a , 13b , 13c . The bis‐enamine derivative 15 reacts also with hydrazine hydrate, guanidine, and hydroxylamine to give bis‐pyrazole 17 , pyrimidine 19 , and isoxazole 21 derivatives, respectively. Some of the newly synthesized compounds show moderate to high antimicrobial activity.     

One‐Pot Synthesis of New Thiadiazolyl‐Pyridines as Anticancer and Antioxidant Agents

The reaction of one equivalents of 5‐acetylthiadiazole with one equivalent of aldehyde in acetic acid and ammonium acetate yielded thiadiazolyl‐pyridine derivatives in a multicomponent reactions. The structures of all the new compounds were elucidated on the basis of elemental analysis and spectral data. The anticancer activities of the synthesized compounds were screened for their activity against human lung carcinoma (A549) and human hepatocellular carcinoma cell lines (HepG2) comparable with cisplatin, and the results showed that most of such compounds exhibit considerable activities. The order of activity against A549 cell line was 4c , 4e , 4a , 6d , 8d , 11 , 12 , 4b , 4f , and 4d . However, compound 4e exhibited the highest activity against HepG2, followed by 4a , 4c , 6d , 8d , 11 , 12 , 4f , 4d , and 4b . On the other hand, compounds 11 , 12 , and 4b showed the highest 2,2‐diphenyl‐1‐picrylhydrazyl free radical scavenging activities. Conclusively, the results of the current study approved the cytotoxic and antioxidant capabilities of the synthesized compounds.     

Synthesis,Structural Characterization,and Biological Evaluation of Novel Substituted 1,3‐Thiazole Derivatives Containing Schiff Bases

In this study, thiazole derivatives containing Schiff bases ( 7a , 7b , 7c , 7d , 7e , 7f , 8a , 8b , 8c , 8d , 8e , 8f , 9a , 9b , 9c , 9d , 9e , 9f ) were synthesized in moderate to high yields (49–94%) using the Hantzsch reaction with thiosemicarbazone derivatives ( 5a , 5b , 5c ) and 2‐bromo‐1‐phenylethanone derivatives ( 6a , 6b , 6c , 6d , 6e , 6f ). The structures of synthesized compounds were elucidated by IR, ¹H NMR, ¹³C NMR, elemental analyses, mass spectroscopy and X‐ray diffraction analysis techniques. Moreover, the synthesized compounds were tested for their in vitro antifungal activity and most of them exhibited moderate to good activity against Fusariumoxysporumf.sp. lycopersici.      

Uses of cyclohexan-1,3-dione for the synthesis of tetrahydrochromeno[3,4-c]chromen derivatives with anti-tumor activities

Cyclohexan-1,3-dione ( 1 ) was used as the key starting material, which reacted with salicylaldehyde ( 2 ) and either malononitrile ( 3a ) or ethyl cyanoacetate ( 3b ) in ethanol containing a catalytic amount of triethylamine to give the 3,4,7,12b-tetrahydrochromeno[3,4-c]chromen-1-one derivatives 5a , b . The latter compounds underwent Gewald's thiophene synthesis through the reaction with either malononitrile or ethyl cyanoacetate to give compounds 6a-d , respectively. On the other hand, compound 5a was used for the synthesis of annulated chromeno[3,4-c]chromen derivatives through its reaction with different chemical reagents. The synthesized compounds were evaluated against the six cancer cell lines A549, HT-29, MKN-45, U87MG, SMMC-7721, and H460 using the standard MTT assay in vitro, with foretinib as the positive control, many compounds expressed high inhibitions. The most active compounds 5b , 6b , 6d , 7 , 9b , 11a , 11b , 13 , 17 , 18b , 20b , 21b , 21e , and 21f were selected for inhibition of five tyrosine kinases and some selected compounds for Pim-1 kinase inhibition. The results showed that compounds 6b , 6d , 11a , 13 , 17 , 20b , and 21e were the most potent compounds with the tyrosine kinases and compounds 6d , 11a , 20b , and 21e were the most potent inhibitors of Pim-1 kinase.     

取代噻吩双酰胺类化合物的设计、 合成及生物活性

利用中间体衍生化方法, 将噻吩环引入到双酰胺类化合物中, 合成了一系列取代噻吩双酰胺类化合物1~3; 目标化合物的结构经核磁共振波谱、 红外光谱及元素分析确认. 生物活性测试结果表明, 化合物1在600 mg/L剂量下对小菜蛾具有良好的杀虫效果, 致死率均为100%, 其中化合物1a和1e在20 mg/L剂量下对小菜蛾的致死率仍达到60%以上; 改变双酰胺结构中的吡唑环得到化合物2和3, 其杀虫活性消失, 说明该类化合物中吡唑环结构对杀虫活性具有关键作用.     

Synthesis of 2,3-disubstituted benzo[b]thiophenes via palladium-catalyzed coupling and electrophilic cyclization of terminal acetylenes

2,3-Disubstituted benzo[b]thiophenes have been prepared in excellent yields via coupling of terminal acetylenes with commercially available o-iodothioanisole in the presence of a palladium catalyst and subsequent electrophilic cyclization of the resulting o-(1-alkynyl)thioanisole derivatives. I(2), Br(2), NBS, p-O(2)NC(6)H(4)SCl, and PhSeCl have been utilized as electrophiles. Aryl-, vinyl-, and alkyl-substituted terminal acetylenes undergo this coupling and cyclization to produce excellent yields of benzo[b]thiophenes. (Trimethylsilyl)acetylene also undergoes this coupling/cyclization process with I(2), NBS, and the sulfur and selenium electrophiles to afford the corresponding 2-(trimethylsilyl)benzo[b]thiophenes. However, cyclization of the silyl-containing thioanisole using Br(2) affords 2,3-dibromobenzo[b]thiophene.     

Thiophenes as traps for benzyne. 3. Diaryl sulfides and the role of dipolar intermediates

The reactions of seven thiophenes with benzyne generated from diphenyliodonium-2-carboxylate (DPIC) under a standard set of conditions led among other products to the formation of alpha- and beta-naphthyl phenyl sulfides 2a and 2b from thiophene (1a) and of 2c and 2d from 2-methylthiophene (1b). Dithienyl sulfides 4a-f were produced from the halothiophenes 1c-g. The structures of the naphthyl sulfides were proven by comparison with authentic samples of 2a-f, thus eliminating one of two possible mechanisms of formation. The remaining mechanism involves [4+2]-cycloaddition of benzyne to thiophene or to an S-phenylthiophenium ylide 10 to give the dipolar 2:1 benzyne/thiophene adduct 8 followed by ring-opening. Stevens-like rearrangements of 11, formed from 10 by proton transfer, may also explain the origin of arylated thiophenes such as 12 and 3 found in some reactions of benzynes with thiophene.     

A facile synthesis of novel 5‐substituted pyridine 2 carboxamide derivatives and their biological evaluation and 3D QSAR studies

A variety of novel 5‐substituted pyridine 2 carboxamides were designed and synthesized using both normal and solvent‐free microwave (MW) irradiation techniques. The results revealed that MW protocol proceeded smoothly under mild reaction conditions in short reaction times, thus avoiding the use of toxic organic solvents. Structural elucidation of the synthesized compounds was carried out on the basis of various spectroscopic methods, such as ¹H NMR, ¹³C NMR, LCMS, and IR. The synthesized compounds were evaluated for their in vitro antimicrobial activity (MIC) using the agar disk diffusion method. Among the various synthetic compounds, compound 3b showed higher potential activity against Escherichia coli than the other compounds. The order of activity against E. coli of the studied compounds is 3b > 3e > 3g > 3h > 3d > 3c > 3a > 3f . Additionally, 2D and 3D structural features of the synthesized derivatives were recognized by the 3D‐QSAR model. This validated model exhibited good internal (r², 0.924) and external prediction (r²pred, 0.851) correlation. The results of QSAR studies concluded that Alog P, the number of hydrogen bond acceptors, and the number of rotatable bonds were necessary features for the activity of the pyridine carboxamide derivatives.     

Synthesis and some transformations of benzo[b]thiophene derivatives

A number of 3-chloro-2-chlorocarbonylbenzo [b] thiophenes with alkyl substituants in various positions of the benzene ring were synthesized by arylation of acrylic acid with the corresponding alkyl-substituted iodobenzenes under the influence of catalytic amounts of palladium acetate and subsequent oxidation of the resulting arylacrylic acids with thionyl chloride. Replacement of the pyridine added in the oxidation reaction by triethylbenzylammonium chloride led to substantial increases in the yields of the desired products. The possibility of conversion of the resulting benzo [b] thiophene derivatives to thiophene ring-unsubstituted benzo[b] thiophenes was shown in the case of 3-chloro-2-chlorocarbonylbenzo [b] thiophene as a result of successive saponification of the 2-chlorocarbonyl group, decarboxylation, and dechlorination.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1618–1622, December, 1982.     

Nitro derivatives of 2-(1-naphthyl) thiophene

2-[1-(3, 4-Dihydronaphythyl)]thiophene, 2-(1-naphthyl)thiophene, 3, 4, 5-triacetoxymercuri-, 3, 4-diacetoxymercuri-5-nitro-, 4, 5-diacetoxymercuri-3-nitro-2-(1-naphthyl)thiophenes and 3, 3, 4-triacetoxymercuri-2[1-(4-nitronaphthyl)]thiophene are synthesized and characterized. Nitration of 2-(1-naphthyl)thiophene with copper nitrate in acetic anhydride leads to formation of two isomeric mono-nitro derivatives, 4-nitro- and 5-nitro-2-(1-naphthyl)thiophene.     

双分子维生素B_(12)模型分子的合成及表征

维生素B_(12)经醇解得到的七甲基钴啉酯1作为起始原料，经酸性水解分别得 到b,c,d,e,f-单酸钴啉酯2b～2f, 2b～2f与3-咪唑基丙胺盐酸盐反应合成了相应的 酰胺钴啉酯衍生物3b～3f, 3b～3f在乙酸的作用下合成了双分子络合维生素B_(12) 模型化合物双-单腈六甲基-N-（3-咪唑基）丙酰胺钴啉酯高氯酸盐5b～5f，并对其 化学结构进行了表征。     

Synthesis and Reactions of Some Heterocyclic Candidates Based on 2‐Amino‐4,5,6,7‐tetrahydrobenzo[b]thiophene Moiety as Anti‐Arrhythmic Agents

In continuation of our previous work, a series of novel thiophene derivatives 4 , 5 , 6 , 8 , 9 , 9a , 9b , 9c , 9d , 9e , 10 , 10a , 10b , 10c , 10d , 10e , 11 , 12 , 13 , 14 , 15 , 16 were synthesized by the reaction of ethyl 2‐amino‐4,5,6,7‐tetrahydrobenzo[b]thiophene‐3‐carboxylate ( 1 ) or 2‐amino‐4,5,6,7‐tetrahydrobenzo[b]thiophene‐3‐carbonitrile ( 2 ) with different organic reagents. Fusion of 1 with ethylcyanoacetate or maleic anhydride afforded the corresponding thienooxazinone derivative 4 and N‐thienylmalimide derivative 5 , respectively. Acylation of 1 with chloroacetylchloride afforded the amide 6 , which was cyclized with ammonium thiocyanate to give the corresponding N‐theinylthiazole derivative 8 . On the other hand, reaction of 1 with substituted aroylisothiocyanate derivatives gave the corresponding thiourea derivatives 9a , 9b , 9c , 9d , 9e , which were cyclized by the action of sodium ethoxide to afford the corresponding N‐substituted thiopyrimidine derivatives 10a , 10b , 10c , 10d , 10e . Condensation of 2 with acid anhydrides in refluxing acetic acid afforded the corresponding imide carbonitrile derivatives 11 , 12 , 13 . Similarly, condensation of 1 with the previous acid anhydride yielded the corresponding imide ethyl ester derivatives 14 , 15 , 16 , respectively. The structures of newly synthesized compounds were confirmed by IR, ¹H NMR, ¹³C NMR, MS spectral data, and elemental analysis. The detailed synthesis, spectroscopic data, LD₅₀, and pharmacological activities of the synthesized compounds are reported.     

Synthesis and Study of the Anodic Behavior of 1,3,4,6-Tetraaryl-2λ 4 δ 2 -thieno[3,4-c]thiophenes

Two heterocyclic compounds based on the thieno[3,4-c]thiophene structure with four aryl substituents were prepared and their behavior in electrooxidation studied. These tetraarylthieno[3,4-c]thiophenes were synthesized in three steps starting from 1,3-dibenzoylmethane in the case of 1,3,4,6-tetraphenyl-2 u 4 i 2 -thieno[3,4-c]thiophene 1a and from 1,3-bis(4'-methoxyphenyl)propane-1,3-dione in the case of 1,3,4,6-tetrakis(4'-methoxyphenyl)-2 u 4 i 2 -thieno[3,4-c]thiophene 1b , a new compound. Both cyclic and hydrodynamic voltamperometric analyses indicate two reversible one-electron oxidation stages for compound 1b , while for compound 1a only the first stage is reversible. The preparative electrooxidation of the two compounds results in the opening of one thiophene ring giving rise to n -keto-thioketones.     

An investigation of condensed heteroaromatic systems including a thiophene ring

The influence of the temperature, of the natures of the initiator and of the initial compound, and of the concentrations of the reactants on the process and nature of the transformations of 2- and 3-alkyl-, 2- and 3-formyl-, and 2- and 3-hydroxymethylbenzo[b]thiophenes under conditions of liquid-phase oxidation with oxygen in the presence of cobalt acetate in acetic acid has been studied. According to their relative ease of oxidation, the homologs and derivatives of benzo[b]thiophene, thiophene, and benzene can be arranged in the following sequence: 3-methylbenzo[b]thiophene > 2-methylbenzo[b]thiophene > 2-methylthiophene > toluene > 3-methylbenzo[b]thiophene dioxide > 2-methylbenzo[b]thiophene dioxide; benzaldehyde > benzo[b]thiophene-3-carbaldehyde > thiophene-2-carbaldehyde > benzo[b]-thiophene-2-carbaldehyde; 3-hydroxymethylbenzo[b]thiophene > 2-hydroxymethylbenzo[b]-thiophene > benzyl alcohol > 2-hydroxymethylthiophene. The liquid-phase oxidation of alkyl-substituted benzo[b]thiophenes can be used to obtain aldehydes, ketones, and acids of the benzo[b]thiophene series.For Communication XXIV, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1026–1033, August, 1973.     

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 Antimicrobial Evaluation of Some New Thiophene Derivatives

2-(2-Cyano-acetylamino)-4,5,6,7-tetrahydro-benzo[b]thiophene-3-carboxamide(3) was used as starting material for synthesis of 4-thiazolidinone, thiazolidine, and thiophene derivatives 6, 7a, b, and 8a, b, respectively. Thiocarbomyl derivative 5, 4-thizolidinone 9, and thioxothiazolidine 10 were obtained from reaction of 3 with thioglycolic acid and phenyl isothiocyanate/sulfur, respectively. Condensation of 3 with selected cyclic ketones and aromatic aldehydes yielded the arylidine derivatives 11a, b and 13, respectively. Refluxing of 11a, b with sulfur and morpholine yielded the thiophene derivatives 12a, b, respectively. Diazocoupling of compound 3 withp-tolyl diazonium chloride yielded the hydrazone derivative 14. The newly synthesized compounds were characterized by infrared, ¹H NMR, and mass spectral studies. Representative compounds of the synthesized product were tested and evaluated as antimicrobial agents. Compound 12b gives very high antimicrobial activity against Ampicillin.