Iron oxide magnetic nanoparticles supported on amino propyl-functionalized KCC-1 as robust recyclable catalyst for one pot and green synthesis of tetrahydrodipyrazolopyridines and cytotoxicity evaluation

In this study, paramagnetic dendritic fibrous nano-silica functionalized by aminopropyltriethoxysilan (Fe₃O₄@KCC-1-nPr-NH₂) was synthesized using a novel hydrothermal protocol and used as a highly efficient, recyclable and heterogeneous nanocatalyst for the synthesis of a wide range of tetrahydrodipyrazolopyridines derivatives ( 5a-5 m ). The influence of different reaction parameters, such as the effects of solvent, temperature, time and concentration of catalyst for the synthesis of tetrahydrodipyrazolopyridine (2a) were studied. This catalyst could be reused for ten consecutive recycles without any considerable loss in its catalytic activity. This novel synthesis method offers some advantages including short reaction time, high yield and simple work-up procedure. Finally, the newly synthesized tetrahydrodipyrazolopyridines derivatives ( 5a-5f ) were characterized by ¹H and ¹³C NMR, IR and CHN.     

Piperidine‐functionalized silica: an efficient and environmentally benign catalyst for Claisen–Schmidt condensation

Piperidine‐functionalized silica as a basic heterogeneous catalyst was synthesized via a simple protocol by condensing silica chloride with piperidine. The catalyst was characterized with various techniques (FT‐IR, solid state NMR, scanning electron microscopy, energy‐dispersive X‐ray, thermogravimetric, elemental, and NH₃ and CO₂ temperature‐programmed desorption analyses). Surface area was also evaluated through Brunauer–Emmett–Teller analysis. Its catalytic activity was evaluated for Claisen–Schmidt condensation under solvent‐free conditions. The catalyst was easily recovered and reused up to five cycles without considerable loss of activity and was not deactivated due to amide formation. Also, this method has attractive advantages such as short reaction time, mild reaction conditions, good to excellent yield of products, easy handling of the catalyst and simple operational procedure. Copyright © 2014 John Wiley & Sons, Ltd.     

Copper Schiff base functionalized polyaniline (Cu‐SB/PANI): A highly efficient polymer based organometallic catalyst for the synthesis of 2‐amino chromene derivatives

Copper Schiff Base functionalized Polyaniline (Cu‐SB/PANI) has been synthesized as an efficient, recyclable and heterogeneous polymer based organometallic catalyst by simple method. The catalyst has been well characterized with different spectroscopic techniques such as FTIR, SEM/EDX, elemental mapping, XRD, TEM, TG, XPS, EPR and ICP‐AES analyses. The catalytic potential of the catalyst has been explored by synthesizing 2‐amino chromene derivatives. The catalyst efficiently catalyzed the reaction affording excellent yield of the products (95–97%) in very short reaction time period (6–8 min). The catalyst could be reused for five times with insignificant loss in catalytic activity.     

A Facile Synthesis of Novel Cyclic Esters of γ‐Keto Acid Derivatives by Heck Coupling Reaction

γ‐Keto acids and esters are highly useful compounds in organic synthesis, because a number of five‐membered carbocycles and various other heterocycles can be readily obtained from them. A number of γ‐keto acids derivatives have been synthesized with high yield by Heck coupling reaction with different alkenes using Pd(OAc)₂ as catalyst in dioxane solvent. The obtained products were characterized by elemental analysis, IR, proton NMR, and mass spectral studies.     

4-芳亚甲基-1-(4’-羧基苯基)-3-甲基吡唑-5-酮的三组分一锅法合成

本文报道了由乙酰乙酸乙酯、对羧基苯肼和芳香醛经三组分一锅法缩合制备4-芳亚甲基-1-(4’-羧基苯基)-3-甲基吡唑-5-酮衍生物的有效方法。实验结果表明,当以乙醇为溶剂,六氢吡啶为催化剂时,所得反应产率最高。所有产物均通过1H NMR,13C NMR,IR和MS技术进行了结构确定。     

Synthesis and characterization of water‐soluble barbiturate‐ and thiobarbiturate‐functionalized polystyrene

The synthesis and characterization of barbiturate‐ and thiobarbiturate‐functionalized polystyrene from polystyrene homopolymer by polymer‐modification reactions is discussed. Polystyrene homopolymer quantitatively functionalized at the para postion with diethyl oxomalonate functionality was subjected to a condensation reaction with urea and thiourea in the presence of sodium methoxide in methanol. This reaction proceeded essentially to quantitative conversion to the barbiturate‐ (BAPS) and thiobarbiturate‐functionalized polystyrenes (TBAPS) as estimated by ¹H NMR, UV, and IR spectroscopies. Thus, several copolymers of styrene with barbiturate‐ and thiobarbiturate‐functionalized styrene were synthesized. The detailed characterizations of quantitatively functionalized polystyrene using gel permeation chromatographic, IR, UV, and ¹H NMR spectroscopic techniques as well as thermogravimetric analysis are discussed. An application of the newly synthesized polymer in removing Cu(II) ions from aqueous solution is demonstrated. This is the first report on the synthesis of BAPS and TBAPS by the polymer‐modification route or otherwise. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 731–737, 2002; DOI 10.1002/pola.10154     

Synthesis,characterization and catalytic evaluation of ZrCl4:Mg(ClO4)2 for the synthesis of 1,3-diaryl-3-(phenylthio)propan-1-one

Herein we demonstrate a novel tandem aldol condensation-thia-Michael addition process using a bimetallic catalyst (ZrCl₄:Mg(ClO₄)₂). The novel bimetallic catalyst performs under very mild conditions. The catalyst helps in the efficient synthesis of β-mercapto carbonyl derivatives from chalcones and thiols in one-pot method. We successfully used the zirconium tetrachloride in combination with magnesium perchlorate in a specific ratio which is considered as green catalyst and efficiently worked for the synthesis of β-mercapto carbonyl derivatives at room temperature. This is the first report which presents the use of ZrCl₄:Mg(ClO₄)₂ without calcination. Significant advantages of this method are that the reaction is performed under mild conditions, shows good selectivity and high yield, within short reaction times and easy workup. This method minimizes waste disposal problems as well, which makes present method highly efficient and convenient. The synthesized bimetallic catalyst was characterized by different analytical techniques such as XRD and SEM. Subsequently, the synthesized β-mercapto carbonyl products were identified by using FTIR, NMR, GC–MS and CHN elemental analyzer.     

Design and synthesis of novel pyrazol-3ylthiazoles

Biheterocyclic compounds in recent years have gained a significant importance in medicinal chemistry. In this paper the synthesis of novel pyrazol-3ylthiazoles through Vilsmeier–Haack reaction using 2-amino thiazoles as precursors is described. Synthesis of twelve new derivatives was accomplished with moderate yield (70–76%). Structures of all the newly synthesized compounds were characterized by spectral (¹H NMR, ¹³C NMR, IR, LC–MS) and elemental analyses.     

One pot three-component synthesis of 5-substituted 1H-tetrazole from aldehyde

A versatile, robust and efficient strategy for the synthesis of vast range of highly functionalized 5-substituted 1H-tetrazole derivatives by using one pot three-component synthesis from various aldehydes, hydroxylamine hydrochloride and sodium azide in presence of a catalytic amount of ceric ammonium sulphate, a non toxic, easily available, inexpensive, unexplored and reusable catalyst is reported. This one-pot synthesis has several advantages such as mild reaction conditions, shorter reaction time, low catalyst loading, good to moderate yields and functional group tolerance making this methodology practically feasible. The synthesized compounds were characterized by ¹H NMR, ¹³C NMR and HRMS.     

Development of an efficient,one-pot,multicomponent protocol for synthesis of 8-hydroxy-4-phenyl-1,2-dihydroquinoline derivatives

A one-pot quick and efficient multicomponent reaction has been developed for the synthesis of a new series of functionalized 8-hydroxy-4-phenyl-1,2-dihydroquinoline derivatives using 30 mol% ammonium acetate in ethanol as solvent. This economical protocol run smoothly to give variety of quinoline derivatives in 55% to 98% yield from inexpensive reagents and catalyst in mild reaction conditions. Various spectroscopic techniques like FTIR, ¹H NMR and ¹³C NMR, MALDI-TOF-MS, and EI-MS were used to study and confirm their structure.     

A bio-waste derived sustainable heterogenous catalyst for Biginelli reaction

This study is targeted at agricultural waste-derived heterogeneous catalysts, which have been effectively employed for Biginelli reaction. The application of cotton waste (Gossypium) derived lignin as a heterogeneous catalyst for C–C bond formation via one pot multicomponent Biginelli reaction. Here we hypothesize that the preparation of bio-waste derived catalyst by high temperature pyrolysis method under anaerobic conditions. The bio-waste derived heterogeneous catalyst (BDC) was well characterized by using different analytical techniques such as BET, SEM, TEM, XRD, DSC, TGA, ICP. The acidity of the catalyst was determined by a Hammett indicator test and titration method. An excellent yield of 6-methyl-2-oxo/thio-4-phenyl substituted-1,2,3,4-tetrahydropyrimidine-5-ethyl carboxylate derivatives was obtained in shorter reaction time (>80% yield in 15–30 min). The catalyst used in these studies has the advantage of being a waste material. Consequently, it is a low-cost, easily prepared, recyclable and environmentally benign. In addition, the use of a biogenic renewable catalyst, its atom economy, and room temperature and solvent-free reaction conditions and the avoidance of column chromatography make the protocol highly significant from green and sustainable chemistry perspectives. The synthesized compounds were characterized by modern analytical techniques like NMR, MS, FT-IR, CHNS analysis. The experimental parameters like % mole of catalyst, mole ratio, temperature and time for reaction completion were also optimized to achieve maximum yield and purity. The surface interaction between BDC and reactant was also studied.     

2-氨基-3-氰基-4-芳基-6-甲氧基-1,4,9,10-四氢萘并[2,1-b]吡喃衍生物的一步合成

以芳醛、丙二腈和7-甲氧基-1,2,3,4-四氢萘-2-酮为原料,在六氢吡啶催化下以乙醇为溶剂,在室温合成了一系列新的2-氨基-3-氰基-4-芳基-6-甲氧基-1,4,9,10-四氢萘并[2,1-b]吡喃衍生物,反应条件温和,产率较高,并通过IR,1H NMR和元素分析表征产物的结构,还通过单晶X射线衍射分析确证产物的构象.     

二氧化硅负载磷钨酸催化合成3,4-二氢嘧啶-2(1H)-酮衍生物

以取代苯甲醛、乙酰乙酸乙酯和尿素为原料,以溶胶凝胶法制备二氧化硅负载的磷钨酸（H3PW12O40/SiO2）为催化剂,催化合成3,4-二氢嘧啶-2(1H)-酮,考察了三组分摩尔比、反应温度、催化剂用量及反应时间对反应收率的影响。 研究表明,H3PW12O40/SiO2是合成3,4-二氢嘧啶-2(1H)-酮的良性催化剂,在取代苯甲醛的用量为0.04 mol,反应温度为90 ℃的条件下,收率可达73.1%~88.4%。 催化剂和产品结构分别经IR、XRD、SEM和1H NMR、IR、MS等技术手段表征。     

氨基酸和酸酐直接反应合成含羧基的酰亚胺类化合物

首次用氨基酸与一系列酸酐直接反应, 合成了20个含羧基的酰亚胺, 对其结构进行了表征. 为含羧基酰亚胺类化合物的合成提供了一种直接、简便的新方法.     

Biguanidine‐functionalized chitosan to immobilize palladium nanoparticles as a novel,efficient and recyclable heterogeneous nanocatalyst for Suzuki–Miyaura coupling reactions

Biguanidine‐functionalized chitosan was synthesized and combined with palladium nanoparticles to yield a recyclable, environmentally benign, heterogeneous catalytic system for the Suzuki–Miyaura C–C coupling reaction. The catalyst was characterized using various techniques. The catalyst was used in Suzuki cross‐coupling reactions of various aryl halides, including less reactive chlorobenzenes, with phenylboronic acid to give biaryls without any additive or ligand. A reusability test demonstrated that the catalyst was highly efficient even after six runs. Solid‐phase poisoning and leaching tests indicated that the catalyst has a heterogeneous nature. Copyright © 2016 John Wiley & Sons, Ltd.     

微波促进苄基溴化锌与肉桂醛的烯基化反应

在Me3SiCl和Pd（PPh3）2Cl2存在下,通过微波辐射带官能团的苄基溴化锌与肉桂醛反应高效地合成了含不同官能团的1,4-二苯基-1,3-丁二烯类化合物,收率65％-95％,其结构经1^H NMR,13^C NMR,IR和MS确证。     

Silica Sulfuric Acid: An Efficient,Reusable, Heterogeneous Catalyst for the One-Pot,Five-Component Synthesis of Highly Functionalized Piperidine Derivatives

A series of highly functionalized piperidine derivatives was synthesized through one-pot, five-component reaction of aldehydes, amines, and β-ketoesters. Silica sulfuric acid efficiently catalyzes the reaction to afford the corresponding piperidine derivatives in good yields. As a representative example, heating of 4-methylaninle, 4-fluorobezaldehyde, and methyl-acetoacetate in methanol in the presence of silica sulfuric acid furnished the corresponding ethyl 2,6-bis(4-fluorophenyl)-1-p-tolyl-4-(p-tolylamino)-1,2,5,6-tetrahydropyridine-3-carboxylate in excellent yield (85%). Most of the synthesized compounds were screened in vitro for their antibacterial and antifungal activities. Most of compounds showed significant antibacterial activity.     

Green synthesis of dihydropyrano[3,2-c]chromene derivatives using amino-terminated PAMAM dendrimer as catalyst

d-Sorbitol-cored PAMAM dendrimer (SOR-G1) was effectively synthesized by the ring opening polymerization of epichlorohydrin. The dendrimer was characterized using different spectroscopic and analytical techniques including IR and NMR spectroscopy, TG–DTA, and GPC. Dihydropyrano[3,2-c]chromene derivatives were synthesized using SOR-G1 as a catalyst, and it was synthesized within 30 min in ethanol/water medium and excellent yield was obtained. SOR-G1 acted as a good base catalyst on the basis of amine capacity and good thermal stability. The prepared dihydropyrano[3,2-c]chromene derivatives were characterized using GCMS, LCMS, IR, ¹H NMR, and ¹³C NMR spectra. The catalyst could be reused up to three reaction cycles without losing its catalytic activity.

Graphic abstract

     

微波辐射下合成5-芳亚甲基-2,3-二芳基-4-噻唑啉酮类化合物

在水介质中,以四丁基溴化铵(TBAB)作催化剂,微波辐射下使芳醛与4-噻唑啉酮反应合成一系列5-芳亚甲基-2,3-二芳基-4-噻唑啉酮类化合物.该反应具有反应时间短、产率高、环境友好、后处理简便等优点.所有化合物均经IR,MS,1H NMR和元素分析确定.同时用X射线衍射法测定了化合物4a的晶体结构.     

Green synthesis of 3,4-dihydropyrimidinones using nano Fe3O4@meglumine sulfonic acid as a new efficient solid acid catalyst under microwave irradiation

Design, synthesis and characterization of nano Fe₃O₄@meglumine sulfonic acid as a new solid acid catalyst for the simple and green one pot multicomponent synthesis of 3,4-dihydropyrimidin-2(1H)-ones/thiones was studied. New solid acid catalyst was prepared through a clean and simple protocol and characterized using FTIR, VSM, TGA, SEM, elemental analysis (CHN) and XRD techniques. Heterogenization of homogeneous catalyst as a green approach is a useful method for enhancing the efficiency of catalyst. Presented study was a new method for attachment of homogeneous highly soluble catalyst (meglumine sulfate) to the magnetite nanoparticle surfaces for preparing a heterogeneous and effective catalyst. Obtained heterogeneous and reusable solid acid catalyst has high performance in the synthesis of Biginelli compounds. The reaction was performed under microwave irradiation as a rapid and green condition. Easy work up as well as excellent yield (90–98%) of products in short reaction times (40–200 s) and reusable catalyst are the main advantages of presented procedure. Reaction products were characterized in details using physical and chemical techniques such as melting point, ¹H NMR, ¹³C NMR and FTIR.