Green Synthetic Methodology Research Articles

Base mediated green synthesis of enantiopure 2-C-spiro-glycosyl-3-nitrochromenes.

A novel green synthetic methodology has been developed to obtain enantiopure (2S)-2-C-spiro-glycosyl-3-nitrochromenes following the oxa-Michael-aldol condensation reaction of sugar derived 3-C-vinyl nitro olefins with substituted salicylaldehydes using Et3N as a base under neat conditions at rt-40 °C. The stereochemistry of the product is confirmed by a single crystal X-ray study. Several advantages are associated with this protocol such as cost effectiveness, easy accessibility, short reaction time, high yields, wide substrate scope and high enantiopurity.

A Sustainable Approach for the Synthesis of Catalytically Active Peroxidase-Mimic ZnS Catalysts

Zinc sulfides are emerging as promising catalysts in different fields such as photochemistry or organic synthesis. Nevertheless, the synthesis of ZnS compounds normally requires the utilization of toxic sulfur precursors, e.g., thiourea which is a contaminant and carcinogenic agent. As a result, new green and sustainable synthetic methodologies are needed. Herein, an innovative, simple, and cheap approach for the synthesis of ZnS carbon composites is reported. Zinc acetate dihydrate was employed as metal precursor while wasted pig bristles were employed as carbon and sulfur source. The phase and the morphology of the compounds were analyzed by XRD, XPS, SEM, and EDX and the surface area was determined by nitrogen physisorption. ZnS carbon materials showed remarkable peroxidase-like catalytic activity for two different model reactions: the liquid-phase selective oxidation of benzyl alcohol and toluene to benzaldehyde (conversions up to 63% and 29% and selectivities up to 86% and 87%, respectively) using hy...

Green synthetic methodology: An evaluative study for impact of surface basicity of MnO2 doped MgO nanocomposites in Wittig reaction

For synthesis of flavoring agent E-ethyl cinnamate in an economic way using Wittig reaction, MnO2 doped MgO nanocomposites were prepared by alkali leached hydrothermal method. The resultant nanocomposites were characterized by XRD, UV-DRS, FT-IR, FESEM, EDAX, XPS and Hammett indicator method. This surface modified MnO2 doped MgO can be used as green solid base for Wittig reaction between benzaldehyde and phosponium salt for synthesis of E-ethyl cinnamate under solvent free approach. Nanocomposite of MgO with MnO2 in combination with green mechanochemical approach seems to be more economic in comparison to pure nanosized MgO under conventional solvent stirring. Both efforts are complementary for promoting surface basic activity of MgO for high-yield synthesis of E-ethyl cinnamate using Wittig reaction. The product ethyl cinnamate has been characterized by HR-MS, IR, 1H NMR.

Greener Biogenic Approach for the Synthesis of Palladium Nanoparticles Using Papaya Peel: An Eco-Friendly Catalyst for C-C Coupling Reaction.

The development of a green and sustainable synthetic methodology still remains a challenge across the globe. Encouraging the prevailing challenge, herein, we have synthesized Pd nanoparticles (Pd NPs) in a green and environmentally viable route, using the extract of waste papaya peel without the assistance of any reducing agents, high-temperature calcination, and reduction procedures. The biomolecules present in the waste papaya peel extract reduced Pd(II) to nanosize Pd(0) in a one-pot green and sustainable process. As a catalyst, the new Pd NPs offer a simple and efficient methodology in direct Suzuki–Miyaura and Sonogashira coupling with excellent yields under mild reaction conditions.

TfOH mediated intermolecular electrocyclization for the synthesis of pyrazolines and its application in alkaloid synthesis.

TfOH mediated easy access to interesting pyrazolines starting from an aldehyde, phenylhydrazine and styrene has been developed. The scope of this synthetic methodology has been explored by synthesizing various 1,3,5-trisubstituted pyrazolines in very good yields with very high regioselectivity. The origin of regioselectivity has been explained by comparing the stability of possible intermediate carbocations. The synthetic utility of a green solvent has been explored by synthesizing some of pyrazolines in a DES medium. The synthetic application of the present methodology is employed in the synthesis of a pyrazoline alkaloid.

ChemInform Abstract: Recent Advancement of Ullmann‐Type Coupling Reactions in the Formation of C—C Bond

AbstractReview: 64 refs.

Recent advancement of Ullmann-type coupling reactions in the formation of C–C bond

The present text discussed about the recent developments and applications of the Ullmann reaction in respect of the C–C bond formation. The major drawback of the Ullmann reaction, i.e., harsh reaction condition has recently been overcome with the development of various synthetic methodologies. Green synthetic methodologies such as metal-, ligand-, and additive free conditions, recyclable heterogenous catalysts, microwave- and ultrasound-assisted synthesis, etc. have got special importance in this field. This text lucidly describes all these recently developed synthetic methodologies which make the century old Ullmann reaction much efficient, effective, economical and attractive in the field of synthetic organic chemistry. On-surface Ullmann coupling for the C–C bond formation, i.e., invoking C–C coupling reactions on a reactive surface has been discussed. All such developments of the Ullmann C–C coupling facilitate its application in the synthesis of bio-active heterocycles, drug-like molecules and natural products which has also been discussed in this text.

Solid-state Synthesis of Polyhedral Oligomeric Silsesquioxane-Supported N-Heterocyclic Carbenes/Imidazolium salts on Palladium Nanoparticles: Highly Active and Recyclable Catalyst

We describe a novel and green synthetic methodology for the fabrication of polyhedral oligomeric silsesquioxane-supported N-heterocyclic carbenes/imidazolium salts on palladium(II) complexes; Pd(II)-MPIm-POSS (1) composite by solid-state annealing between Pd(OAc)2 and octakis(3-(1-methylimidazolium)propyl) octasilsesquioxane without added base. Subsequently, arylboronic acid based in situ or ex situ reduction of 1 in aqueous ethanol produces polyhedral oligomeric silsesquioxane-supported N-heterocyclic carbenes/imidazolium salts on palladium nanoparticles; Pd(0)-nano-POSS (2) composite, consisting of monodispersed and N-heterocyclic carbene (NHC) stabilized Pd nanoparticles of very small size (3.0 ± 1.5 nm). Nanocatalyst 2 is a highly efficient and easily recyclable homogeneous catalyst for Suzuki-Miyaura cross-coupling reactions with TOF up to 1670 h−1.

Synthesis of nanoparticles composed of silver and silver chloride for a plasmonic photocatalyst using an extract from a weed Solidago altissima (goldenrod)

Phytosynthesis of nanomaterials is advantageous since it is economical, ecofriendly, and simple, and, what is more, in the synthetic protocols, nontoxic chemicals and biocompatible materials are used. Here, a green synthetic methodology of nanoparticles (NPs) composed of silver (Ag) and silver chloride (AgCl) NPs is developed using a leaf extract of Solidago altissima as a reducing agent for the first time. Utilization of a terrestrial weed for the synthesis of Ag and AgCl NPs is a novel environmentally friendly approach considering that no toxic chemicals, external halide source, or elaborate experimental procedures are included in the process. The optical properties and elemental compositions of as-synthesized Ag and AgCl NPs are well characterized, and the degradation of an organic dye, i.e., rhodamine B (RhB), is investigated using the Ag and AgCl NPs. We find that degradation of RhB is effectively achieved thanks to both surface plasmon resonance and semiconductor properties of Ag and AgCl NPs. The surface-enhanced Raman scattering and antibacterial activities are also examined. The present approach to the synthesis of NPs using a weed may encourage the utilization of hazardous plants for the creation of novel nanomaterials.

Microwave-Assisted Green Production of Furfural from D-xylose of Sugarcane Bagasse

D-xylose is a component of sugarcane bagasse that can be used as a renewable resource for the production of a variety of chemicals. By means of catalytic reactions in an aqueous medium, it was determined that D-xylose can efficiently be converted into furfural by the application of microwave as a green synthetic methodology. The highest yields of furfural were obtained at a HCl concentration of 4 mg/mL. When the reaction was performed at 200 °C, an optimum yield of 64% of furfural was observed after 10 min of reaction time, with 95% of the D-xylose being converted.

Base mediated direct C–H amination for pyrimidines synthesis from amidines and cinnamaldehydes using oxygen as green oxidants

Abstract A direct metal-free C–H amination reaction of cinnamaldehydes and amidines to realize the synthesis of polysubstituted pyrimidines was developed in the presence of base. This greener synthetic methodology provides a straightforward approach to the synthesis of a variety of pyrimidine derivatives under mild reaction condition using oxygen as sole oxidants.

C(sp3)–H functionalization of methyl azaarenes: a calcium-catalyzed facile synthesis of (E)-2-styryl azaarenes and 2-aryl-1,3-bisazaarenes

Alkaline earth (Ca2+) catalyzed sp3 C–H functionalization of methyl azaarenes for the synthesis of biologically important (E)-2-styryl azaarenes, 2-aryl-1,3-bisazaarenes and 3,3-bisazaarenyl indolinones has been described. Initially methyl azaarenes react with aryl aldehydes to give β-hydroxy derivatives, which undergo Ca(II) catalyzed thermodynamic elimination to give the styryl azaarenes in a single step. Similarly it may undergo SN1 reaction to give 2-aryl-1,3-bisazaarenes and 3,3-bisazaarenyl indolinones (if isatin used as the electrophile). This green synthetic methodology enjoys the simple reaction procedures, solvent free conditions, step economy, substrate diversity and high yields of the products in short time.

Green synthesis of fluorescence carbon nanoparticles from yum and application in sensitive and selective detection of ATP.

Fluorescent carbon nanoparticles (CPs), a fascinating class of recently discovered nanocarbons, have been widely known as some of the most promising sensing probes in biological or chemical analysis. In this study, we demonstrate a green synthetic methodology for generating water-soluble CPs with a quantum yield of approximately 24% via a simple heating process using yum mucilage as a carbon source. The prepared carbon nanoparticles with an ~10 nm size possessed excellent fluorescence properties, and the fluorescence of the CPs was strongly quenched by Fe(3+), and recovered by adenosine triphosphate (ATP), thus, an 'off' and 'on' system can be easily established. This 'CPs-Fe(3+)-ATP' strategy was sensitive and selective at detecting ATP with the linear range of 0.5 µmol L(-1) to 50 µmol L(-1) and with a detection limit of 0.48 µmol L(-1).

ChemInform Abstract: Efficient Synthesis of Fused Pyrazoles via Simple Cyclization of O‐Alkynylchalcones with Hydrazine.

Abstract The synthesis of pyrazole derivatives from o-alkynylchalcones and hydrazine via simple cyclization is described. This greener synthetic methodology provides a straightforward approach to the synthesis of a variety of pyrazole derivatives under mild reaction condition.

ChemInform Abstract: Catalysis via Sol‐Gel Acid Silicas: An Important Chemical Technology for 2nd Generation Biorefineries

AbstractReview: [57 refs.

Efficient synthesis of fused pyrazoles via simple cyclization of o-alkynylchalcones with hydrazine

Abstract The synthesis of pyrazole derivatives from o-alkynylchalcones and hydrazine via simple cyclization is described. This greener synthetic methodology provides a straightforward approach to the synthesis of a variety of pyrazole derivatives under mild reaction condition.

Clean and fast cross-coupling of aryl halides in one-pot.

Unsymmetrically coupled biaryls are synthesized in high yield starting from different aryl bromides and bis(pinacolato)diboron by carrying out the Miyaura borylation reaction followed by the Suzuki–Miyaura reaction in the same reaction pot over 1–2 mol % SiliaCat DPP-Pd. The SiliaCat DPP-Pd catalyst is air-stable and the method does not require the use of inert conditions. The use of non-toxic isopropanol or 2-butanol as reaction solvent further adds to the environmental benefits of this new green synthetic methodology.

Facile synthesis of ninhydrin and isatin based hydrazones in water using PEG-OSO3H as a highly efficient and homogeneous polymeric acid-surfactant combined catalyst

Abstract The synthesis of a series of biologically important ninhydrin and isatin based hydrazones has been carried out by refluxing easily synthesized novel N ′-(chloro-aryl-methylene)- tert -butylcarbazates with ninhydrin and isatins in the presence of PEG-OSO 3 H as catalyst in water medium. The dual characteristic of PEG-OSO 3 H as a Bronsted acid as well as a phase-transfer catalyst is successfully exploited in this synthesis. Reduced reaction time, operational simplicity, excellent yields of the products with high purity, and more importantly, easy recoverability, and reusability of the homogeneous polymeric catalyst make the reaction an attractive, economic, and sustainable green synthetic methodology.

ChemInform Abstract: Significant Heterogeneous Carbonate Salt Catalyzed Acetylation of Alcohols via a Transesterification Process with Carbonate Salt‐Activated Alcohol 1H NMR Evidence.

AbstractA simple, mild, cheap and green synthetic methodology to produce esters as useful intermediates in organic syntheses is described.

Regioselective Synthesis of Diltiazem Analogue Pyrazolo[4,3-c][1,5]benzothiazepines and Antifungal Activity

A dry media procedure has been developed for the synthesis of a series of new class of pyrazolo [4,3-c][1,5]benzothiazepines 6 under microwave irradiation using montmorillonite K10 as solid support. The catalyst can be recovered and reused. Thus, the procedure provides a simple and green synthetic methodology under environmentally friendly conditions. Antifungal screening of synthesized compounds has shown promising activity. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.