Solvent-free Protocol Research Articles

Preparation of sulfur–MOF composites and their application in the Willgerodt–Kindler reaction

A convenient MOF-assisted solvent-free protocol for Willgerodt–Kindler reaction with a reusable sulfur carrier is demonstrated.

Solvent-free synthesis, biological evaluation and in silico studies of novel 2-amino-7-(bis(2-hydroxyethyl)amino)-4H-chromene-3-carbonitrile derivatives as potential a-amylase inhibitors

Despite a wide range of kinase inhibitory activities exhibited by 2-amino-4H-chromenes, their potential application towards α-amylase inhibition remained rarely explored to date. For that purpose, a series of new 2-amino-7-(bis(2-hydroxyethyl)amino)-4(phenyl)-4H-chromene-3-carbonitrile derivatives has been synthesized via piperidine catalyzed solvent-free protocol and evaluated for their antidiabetic activity as potential α-amylase inhibitors. The dose-dependent in vitro α-amylase inhibition study revealed that, most of these compounds exhibited significant antidiabetic activity having more than 50 % α-amylase inhibition at the dose of 10 µg/mL. Among these, compound 5b was more potent than acarbose with 91 % inhibition of α-amylase and IC50 of 3.60 ± 0.01 µg/mL. Enzyme kinetic studies to estimate mode of inhibition showed that inhibition of α-amylase by compound 5b was competitive type with a Ki value of 0.97 µg/mL. Further, in silico studies of targeted compounds reinforced the results being involved in favorable binding interactions within the active site of α-amylase. Moreover, the in silico predicted properties of compound 5b regarded as a non-toxic and safer antidiabetic agent.

Aza-Michael Additions of Benzylamine to Acrylates Promoted by Microwaves and Conventional Heating Using DBU as Catalyst via Solvent-Free Protocol

In recent years, the use of solvent-free reactions represents a challenge for organic chemists, since it would help to optimize methodologies and contribute to the development of sustainable chemistry. In this regard, our research group has intensified efforts in the search for reactions that can be carried out in the absence of a solvent. In this paper, we present a protocol for the aza-Michael addition of benzylamine to α,β-unsaturated esters to prepare N-benzylated β-amino esters in the presence of catalytic amounts of DBU (0.2 eq) via solvent-free reaction. Depending on the α,β-unsaturated esters, we observed a reduction in reaction times, with good to excellent yields for aza-Michael addition.

Synthesis of 1, 8-dioxodecahydroacridines using core–shell structured Fe3O4@MgO MNP's: a solvent-free protocol

Synthesis of 1, 8-dioxodecahydroacridines using core–shell structured Fe3O4@MgO MNP's: a solvent-free protocol

Synthesis of 3-Aminoalkylated Indoles Using Heterogeneous MgFe2O4 Nanoparticles Under Microwave Irradiation in One-Pot Three-Component System

AbstractA series of 3-aminoalkylated indoles are efficiently synthesised in a one-pot three-component reaction under microwave irradiation. Magnesium ferrite (MgFe2O4) nanoparticles (10 mol%) have been used as heterogeneous catalyst, which may easily be recovered by application of an external magnet and the recovered catalyst can be reused at least for five runs without affecting the efficiency of the catalyst. The solvent-free protocol developed has advantages of less reaction time, high yields, and easy workup, and the protocol is applicable to various acid base sensitive functional groups present in the substrate. The reported methodology is highly suitable especially for primary amines in addition to secondary amines as one of the components.

HiSorb sorptive extraction for determining salivary short chain fatty acids and hydroxy acids in heart failure patients

Variations in salivary short-chain fatty acids and hydroxy acids (e.g., lactic acid, and 3-hydroxybutyric acid) levels have been suggested to reflect the dysbiosis of human gut microbiota, which represents an additional factor involved in the onset of heart failure (HF) disease. The physical–chemical properties of these metabolites combined with the complex composition of biological matrices mean that sample pre-treatment procedures are almost unavoidable. This work describes a reliable, simple, and organic solvent free protocol for determining short-chain fatty acids and hydroxy acids in stimulated saliva samples collected from heart failure, obese, and hypertensive patients. The procedure is based on in-situ pentafluorobenzyl bromide (PFB-Br) derivatization and HiSorb sorptive extraction coupled to thermal desorption and gas chromatography-tandem mass spectrometry. The HiSorb extraction device is completely compatible with aqueous matrices, thus saving on time and materials associated with organic solvent-extraction methods. A Central Composite Face-Centred experimental design was used for the optimization of the molar ratio between PFB-Br and target analytes, the derivatization temperature, and the reaction time which were 100, 60 °C, and 180 min, respectively. Detection limits in the range 0.1–100 µM were reached using a small amount of saliva (20 µL). The use of sodium acetate-1-13C as an internal standard improved the intra- and inter-day precision of the method which ranged from 10 to 23%. The optimized protocol was successfully applied for what we believe is the first time to evaluate the salivary levels of short chain fatty acids and hydroxy acids in saliva samples of four groups of patients: i) patients admitted to hospital with acute HF symptoms, ii) patients with chronic HF symptoms, iii) patients without HF symptoms but with obesity, and iv) patients without HF symptoms but with hypertension. The first group of patients showed significantly higher levels of salivary acetic acid and lactic acid at hospital admission as well as the lowest values of hexanoic acid and heptanoic acid. Moreover, the significant high levels of acetic acid, propionic acid, and butyric acid observed in HF respect to the other patients suggest the potential link between oral bacteria and gut dysbiosis.

Ultra-fast solvent-free protocol remodels the large-scale synthesis of carbon dots for nucleolus-targeting and white light-emitting diodes

Carbon dots (CDs) provides unprecedented opportunities for optical applications due its unique properties, but the energy-extensive consumption, high-risk factor and time-consuming synthesis procedure greatly hinders its industrialization process. Herein, we proposed an ultra-low energy consumption solvent-free synthetic strategy for fast preparing green/red fluorescence carbon dots (G-/R-CDs) using m-/o-phenylenediamine and primary amine hydrochloride. The involvement of primary amine hydrochloride can improve the formation rate of G-CDs/R-CDs through effectively absorbing microwave energy and providing acid react environment. The developed CDs exhibit good fluorescence efficiency, optical stability and membrane permeability for dexterous bioimaging in vivo. Based on inherently high nitrogen content, the G-CDs/R-CDs possess excellent nuclear/nucleolus targeting ability, and were successfully applied for screening cancer and normal cells. Furthermore, the G-CDs/R-CDs were further applied for fabricating high-safety and high-color rendering index white light-emitting diodes, providing a perfect candidate for indoor lighting. This study opens up new horizons for advancing practical applications of CDs in related fields of biology and optics.

Strategic One-pot Synthesis of Glycosyl Annulated Phosphorylated/ Thiophosphorylated 1,2,3-Triazole Derivatives Using CuFe2O4 Nanoparticles as Heterogeneous Catalyst, their DFT and Molecular Docking Studies as Triazole Fungicides

Abstract:In the present study, we have introduced an efficient solvent-free protocol for the synthesis of glycosyl annulated phosphorylated/thiophosphorylated 1,2,3-triazole derivatives using reusable CuFe2O4 magnetic nanoparticles as a heterogeneous catalyst with the protocols of popular click chemistry approach. Quantum chemical calculations of all the reactants and products have been calculated using density functional theory with Spartan-18 software. In addition, the molecular docking studies of all the glycosyl annulated phosphorylated/thiophosphorylated 1,2,3- triazole derivatives have been studied as effective fungicides against CaCYP51 (PDB ID 5EQB), protein of P. infestans effector target site (PDB ID: 2NAR), and SsCYP51(PDB code: 6CR2) using Autodock Vina and Discovery Studio software. Among the three different proteins, the binding energies of the compounds (5a-d) with CaCYP51 (PDB ID 5EQB) have shown better results in the range of 7.0 to 7.4 kcal/mol. Hence, these compounds may be used as strong fungicides for the inhibition of CaCYP51 (PDB ID 5EQB). In conclusion, the synthesized compounds may be better useful in agrochemical applications as vital fungicides.

An efficient, green and solvent-free protocol for one-pot synthesis of 1,4-dihydropyridine derivatives using a new recyclable heterogeneous catalyst

A new and efficient catalyst was designed and synthesized (Zn/Cr-Layered double hydroxide@(3-chloropropyl) trimethoxysilane @1,3-benzenedisulfonyl amide@Ni), and then fully validated using various techniques such as FT-IR, TGA, FESEM, EDX, X-ray and mapping. To show the efficiency of the prepared catalyst, its catalytic activity was used in the synthesis of 1,4-dihydropyridine derivatives in green and one-pot four-component conditions. The results showed that all products were obtained under solvent-free conditions, with very short reaction time, at room temperature with excellent efficiency (99%) and high purity. In addition, the catalyst was easily recovered and reused five consecutive times without a significant reduction in catalytic activity.

Direct amidation of acids in a screw reactor for the continuous flow synthesis of amides.

A simple and efficient solvent-free protocol for continuous flow synthesis of amides at room temperature is developed using easily available starting materials. N-(3-Dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (EDC.HCl) was used as the reagent for the formation of an amide bond without using any metal catalyst or additives. A jacketed screw reactor when operated over a residence time of 30 300 s helped achieve almost complete conversion. This approach is extended for the synthesis of 36 derivatives and 2 bioactive molecules using different substrates having different aliphatic mono and di-acids as well as aromatic acids, including aromatic hetero-acid compounds and phenyl hydrazine. The target amide was scaled up to 100 g with an average 90% yield.

(Battery Division Postdoctoral Associate Research Award Sponsored by MTI Corporation and the Jiang Family Foundation) 3D Printing of Batteries: Fiction or Reality?

Motivated by the request to build shape-conformable flexible, wearable and customizable batteries while maximizing the energy storage and electrochemical performances, additive manufacturing (AM) appears as a revolutionary discipline. Battery components such as electrodes, separator, electrolyte, current collectors and casing can be tailored with any shape, allowing the direct incorporation of batteries and all electronics within the final three-dimensional object. AM also paves the way toward the implementation of complex 3D electrode architectures that could enhance significantly the power battery performances. Transitioning from conventional 2D to complex 3D lithium-ion battery (LIB) architectures will increase the electrochemically active surface area, enhance the Li+ diffusion paths, thus leading to improved specific capacity and power performance [1]. Our recent modeling studies [2] involving the simulation of a classical Ragone plot illustrated that a gyroid 3D battery architecture has +158% performance at a high current density of 6C, in comparison to planar geometry.In this presentation, an overview of current trends in energy storage 3D printing will be discussed [3-11]. A summary of our recent works on lithium-ion battery 3D printing via Thermoplastic Material Extrusion / Fused Deposition Modeling will be presented [12-16]. The development of printable composite filaments (Graphite-, LiFePO4-, Li2TP-, PEO/LiTFSI-, SiO2-, Ag/Cu-based) corresponding to each part of a LIB (electrodes, electrolyte, separator, current collectors), and the importance of introducing a plasticizer (polyethylene glycol dimethyl ether average Mn 500 for polylactic acid) as an additive to enhance the printability will be addressed. Printing of the complete LIB in a single step using multi-material printing options, and the implementation of a solvent-free protocol [14] will also be discussed. Second part of this presentation will be dedicated to AM of batteries by means of Vat Photopolymerization (VPP) processes, including stereolithography, digital light processing and two-photon polymerization (offering a greater resolution down to 0.1μm), to print high resolution battery components [10]. Composite resins formulation approaches based on the introduction of solid battery particles or precursor salts will be introduced [17, 18]. Finally, an overview of our ongoing project dedicatedto AM of sodium-ion batteries from resources available on the Moon and Mars will be presented. Due to its relative abundance in the Lunar regolith, the development of a composite photocurable resin loaded with TiO2 negative electrode material and conductive additives, to feed a VPP printer, will be discussed [18].[1] Long et al., Three-dimensional battery architectures, Chemical Reviews 104(10) (2004) 4463-4492.[2] Maurel et al., Considering lithium-ion battery 3D-printing via thermoplastic material extrusion and polymer powder bed fusion, Additive Manufacturing (2020) 101651.[3] Maurel et al., Overview on Lithium-Ion Battery 3D-Printing By Means of Material Extrusion, ECS Transactions 98(13) (2020) 3-21.[4] Ragones et al., Towards smart free form-factor 3D printable batteries, Sustainable Energy & Fuels 2(7) (2018) 1542-1549.[5] Reyes et al., Three-Dimensional Printing of a Complete Lithium Ion Battery with Fused Filament Fabrication, ACS Applied Energy Materials 1(10) (2018) 5268-5279.[6] Yee et al., Hydrogel-Based Additive Manufacturing of Lithium Cobalt Oxide, Advanced Materials Technologies 6(2) (2021).[7] Saccone et al., Understanding and mitigating mechanical degradation in lithium–sulfur batteries: additive manufacturing of Li2S composites and nanomechanical particle compressions, Journal of Materials Research (2021).[8] Tagliaferri et al., Direct ink writing of energy materials, Materials Advances 2(2) (2021) 25.[9] Sun et al., 3D Printing of Interdigitated Li-Ion Microbattery Architectures, Advanced Materials 25(33) (2013) 4539-4543.[10] Maurel et al., Toward High Resolution 3D Printing of Shape-Conformable Batteries via Vat Photopolymerization: Review and Perspective, IEEE Access 9 (2021) 140654-140666.[11] Seol et al., All-Printed In-Plane Supercapacitors by Sequential Additive Manufacturing Process, Acs Applied Energy Materials 3(5) (2020) 4965-4973.[12] Maurel et al., Highly Loaded Graphite-Polylactic Acid Composite-Based Filaments for Lithium-Ion Battery Three-Dimensional Printing, Chemistry of Materials 30(21) (2018) 7484-7493.[13] Maurel et al., Three-Dimensional Printing of a LiFePO4/Graphite Battery Cell via Fused Deposition Modeling, Scientific Reports 9(1) (2019) 18031.[14] Maurel et al., Environmentally Friendly Lithium-Terephthalate/Polylactic Acid Composite Filament Formulation for Lithium-Ion Battery 3D-Printing via Fused Deposition Modeling, ECS Journal of Solid State Science and Technology 10(3) (2021) 037004.[15] Maurel et al., Poly(Ethylene Oxide)-LiTFSI Solid Polymer Electrolyte Filaments for Fused Deposition Modeling Three-Dimensional Printing, Journal of the Electrochemical Society 167(7) (2020).[16] Maurel et al., Ag-Coated Cu/Polylactic Acid Composite Filament for Lithium and Sodium-Ion Battery Current Collector Three-Dimensional Printing via Thermoplastic Material Extrusion, Frontiers in Energy Research 9(70) (2021).[17] Martinez et al., Additive Manufacturing of LiNi1/3Mn1/3Co1/3O2 battery electrode material via vat photopolymerization precursor approach, (submitted).[18] Maurel et al., Vat Photopolymerization Additive Manufacturing of Sodium-Ion Battery TiO2 Negative Electrodes from Lunar In-Situ Resources, (submitted).

On the microstructures of the bulk of P3HT amorphous films obtained from two protocols: Insights from molecular dynamics simulations

An influential factor for the microstructure of semiconductor polymer films is the solvent chosen for their processing and subsequent performance as an active layer in electronic and optical devices. In this paper, we address the solvent-polymer interplays by reporting a comparison between the microstructure of the bulk of poly(3-hexylthiophene) (P3HT) films formed from two different simulation methodologies: using the o-dichlorobenzene (ODCB) as an aggregation chain parameter and a solvent-free protocol. In comparison to the length of an ideal planar chain, the solvent caused an average reduction of 12% of oligomer chains. Whereas, in the other film, the reduction was around 30%. Furthermore, the solvent allowed pathways of π-interactions due to the cohesional-like distribution of the chains, indicating that the solvent also induces chain orientation affecting its microstructure.

An Eco-Friendly Synthetic Approach through C(sp3)-H Functionalization of the Viral Fusion “Spike Protein” Inhibitors

The use of organic chemistry to synthesize bio-relevant molecules has been a prime interest of the drug discovery sentients. Recently, our group found 2-styryl substituted quinoline as an anticancer and viral fusion inhibitor through the binding of the gp-41 spike protein. So, we through to synthesize various molecules with an eco-friendly approach. However, various approaches have been reported with the metal, additive, base, and acids to synthesize highly important 2-styrylquinoline from the 2-alkyl quinoline. Still, none of the approaches was reported with the restricted 4-hydroxyquinoline substrate because of their dual nucleophilic nature. The selectivity raises an important issue in this concern substrate. The present protocol overcomes the dual nucleophilic character of the hydroxyl-linked substrate through an optimized eco-friendly sp3 C-H activation approach. The designed protocol for synthesizing gp-41 inhibitors as viral entry inhibitors claimed as metal, acid, and base along with the solvent-free protocol.

An efficient, catalyst and solvent free Staudinger phosphite reaction for the synthesis of phosphoramidates under mild conditions

An efficient, catalyst-free and solvent-free protocol has been developed for the synthesis of phosphoramidates. This method can be used to synthesize phosphoramidates from diverse starting materials including aryl/benzyl and alkyl azides at room temperature. The synthesis is simple, selective and high yielding with notably a very short reaction time. The process involves mild reaction conditions which allow for sensitive functionalities and protecting groups to be used in the developed protocol that is of great advantage and could provide valuable reference for the construction of more complex heterocyclic linked phosphoramidate systems with biological and medicinal importance.

A green, an efficient and viable approach for the synthesis of novel 4H-pyran-indolin-2-one derivatives via a one-pot reaction by grinding method

• A simplistic and rapid protocol using Grinding method. • Synthesis of novel 4 H -pyran-indolin-2-one derivatives. • One-pot/two-component and solvent-free protocol. • Excellent yields (89 to 98%) in short reaction times (< 10 min). An highly efficient and green approach for the synthesis of novel 4 H -pyran-indolin-2-one analogues by the reaction of various isatins with 4 H -pyran-4-one using NaHCO 3 as catalyst under solvent-free, and grinding conditions at room temperature has been showed with good to excellent product yields (89-98%). All the synthesized target compounds has been categorized by various spectroscopic techniques ( 1 H NMR, 13 C NMR, HRMS and FT-IR). This novel protocol has several benefit of mild reaction condition, normal grinding, easy available catalyst, economy, environmentl-friendly, short reaction times (≤ 5 minutes), excellent product yields, and absence of any tedious workup.

Base and metal free true recyclable medium for Knoevenagel condensation reaction in SDS-ionic liquid-aqueous miceller composite system

This paper presents for the first time a base and metal free procedure for Knoevenagel condensation reaction in a neutral medium comprises water-SDS-imidazolium ionic liquid composite system. Knoevenagel condensation products from the different aromatic aldehydes and active methylene compounds such as malononitrile, ethyl cyanoacetate or cyano acetic acid provides good to excellent yields in all cases examined at 80 °C. The developed protocol has several advantages such as chromatography and organic volatile solvent free protocol, short reaction time and recyclability of catalyst including reaction waste. The reaction is believed to proceed in the hydrophobic cavity of the micelle formed in the medium which was proved by dynamic light scattering studies.

Lithium-Ion Battery 3D Printing: From Thermoplastic Material Extrusion to Vat Photopolymerization Process

Transitioning from conventional 2D to complex 3D lithium-ion battery (LIB) architectures will increase electrochemically active surface area and lithium-ion diffusion paths, leading to improved specific capacity and power performance [1]. Our recent in-depth modeling studies and preliminary experiments [2] involving the simulation of a classical Ragone plot that exhibits the energy-power relationship illustrated that a gyroid 3D battery architecture has +158% performance at a high current density of 6C, in comparison to planar geometry. The fabrication of complex electrodes has been widely investigated through an electrochemically-assisted templated growth of current collector arrays, followed by electrophoretic deposition of the electroactive material [3]. However, such an approach is limited in geometries, and the interpenetration of both electrode networks often results in short circuits due to surface defects. The latter can be addressed with the geometric freedom of additive manufacturing, colloquially known as 3D printing, which paves the way toward fabricating complex shape-conformable battery components [4]. Here, a summary of our recent works on lithium-ion battery 3D printing via thermoplastic material extrusion will be presented [5-9]. In particular, the development of printable composite filaments (Graphite-, LiFePO4-, Li2TP-, PEO/LiTFSI-, SiO2-, Ag/Cu-based) corresponding to each part of a classical LIB (electrodes, electrolyte, separator, current collectors), as well as the importance of introducing an adequate plasticizer (such as poly(ethylene glycol) dimethyl ether average Mn 500 for polylactic acid) as an additive to enhance both printability and further electrochemical performances, will be addressed. Printing of the complete LIB in a single step using multi-material printing options, and the implementation of a solvent-free protocol [7] will also be discussed. Finally, the capability of vat photopolymerization processes, including stereolithography, digital light processing and two-photon polymerization (offering a greater resolution down to 0.1µm), to print high resolution LIB components will be presented.[1] J.W. Long, B. Dunn, D.R. Rolison, H.S. White, Three-dimensional battery architectures, Chemical Reviews 104(10) (2004) 4463-4492.[2] A. Maurel, M. Haukka, E. MacDonald, L. Kivijärvi, E. Lahtinen, H. Kim, M. Armand, A. Cayla, A. Jamali, S. Grugeon, L. Dupont, S. Panier, Considering lithium-ion battery 3D-printing via thermoplastic material extrusion and polymer powder bed fusion, Additive Manufacturing (2020) 101651.[3] L. Taberna, S. Mitra, P. Poizot, P. Simon, J.M. Tarascon, High rate capabilities Fe3O4-based Cu nano-architectured electrodes for lithium-ion battery applications, Nature Materials 5(7) (2006) 567-573.[4] H. Ragones, S. Menkin, Y. Kamir, A. Gladkikh, T. Mukra, G. Kosa, D. Golodnitsky, Towards smart free form-factor 3D printable batteries, Sustainable Energy & Fuels 2(7) (2018) 1542-1549.[5] A. Maurel, M. Courty, B. Fleutot, H. Tortajada, K. Prashantha, M. Armand, S. Grugeon, S. Panier, L. Dupont, Highly Loaded Graphite-Polylactic Acid Composite-Based Filaments for Lithium-Ion Battery Three-Dimensional Printing, Chemistry of Materials 30(21) (2018) 7484-7493.[6] A. Maurel, S. Grugeon, B. Fleutot, M. Courty, K. Prashantha, H. Tortajada, M. Armand, S. Panier, L. Dupont, Three-Dimensional Printing of a LiFePO4/Graphite Battery Cell via Fused Deposition Modeling, Scientific Reports 9(1) (2019) 18031.[7] A. Maurel, R. Russo, S. Grugeon, S. Panier, L. Dupont, Environmentally Friendly Lithium-Terephthalate/Polylactic Acid Composite Filament Formulation for Lithium-Ion Battery 3D-Printing via Fused Deposition Modeling, ECS Journal of Solid State Science and Technology 10(3) (2021) 037004.[8] A. Maurel, M. Armand, S. Grugeon, B. Fleutot, C. Davoisne, H. Tortajada, M. Courty, S. Panier, L. Dupont, Poly(Ethylene Oxide)-LiTFSI Solid Polymer Electrolyte Filaments for Fused Deposition Modeling Three-Dimensional Printing, Journal of the Electrochemical Society 167(7) (2020).[9] A. Maurel, H. Kim, R. Russo, S. Grugeon, M. Armand, S. Panier, L. Dupont, Ag-Coated Cu/Polylactic Acid Composite Filament for Lithium and Sodium-Ion Battery Current Collector Three-Dimensional Printing via Thermoplastic Material Extrusion, Frontiers in Energy Research 9(70) (2021).

Metal-Free Synthesis of Heteroaryl Amines or Their Hydrochlorides via an External-Base-Free and Solvent-Free C-N Coupling Protocol.

Herein, a metal-free and solvent-free protocol was developed for the C-N coupling of heteroaryl halides and amines, which afforded numerous heteroaryl amines or their hydrochlorides without any external base. Further investigations elucidated that the basicity of amines and specific interactions derived from the X-ray crystallography analysis of 3j'·HCl played pivotal roles in the reactions. Moreover, this protocol was scalable to gram scales and applicable to drug molecules, which demonstrated its practical value for further applications.

Preparation of a novel, efficient, and recyclable magnetic catalyst, Cu(II)-OHPC-Fe3O4 nanoparticles, and a solvent-free protocol for the synthesis of coumarin derivatives

Cu(II) supported on 5-oxo-4,5-dihydro-pyrrole-3-carboxylic acid functionalized Fe3O4 nanoparticles (Cu(II)-OHPC-Fe3O4) as a new magnetic nanocatalyst was prepared and characterized by ICP-AES, FT-IR, XRD, SEM, TEM, TGA, XRD, VSM and EDX techniques. Prepared nanocatalyst (Cu(II)-OHPC-Fe3O4) is employed for Pechmann reactions between different substituted phenols and ethyl acetoacetate to obtain new products of coumarin derivatives in good to excellent yields. This green catalyst was easily removed, reused several times with no significant loss of its activity and provided clean synthesis with excellent yield and reduced time.

Synthesis of 1-indolyl-3,5,8-substituted γ-carbolines: one-pot solvent-free protocol and biological evaluation

1,5-Disubstituted indole-2-carboxaldehyde derivatives 1a–h and glycine alkyl esters 2a–c are shown to undergo a novel cascade imination-heterocylization in the presence of the organic base DIPEA to provide 1-indolyl-3,5,8-substituted γ-carbolines 3aa–ea in good yields. The γ-carbolines are fluorescent and exhibit anticancer activities against cervical, lung, breast, skin, and kidney cancer cells.