Optimization of the photochemical generation of trifluoronitromethane,CF3NO2, and a refined purification technique

The gas-phase photochemical generation of CF₃NO₂ from CF₃I and NO₂ was found to be equilibrium limited. The formation of CF₃NO₂ is favored at low pressure and high temperature, where the concentration of the reactive species NO₂ is the greatest, and unfavored at high pressure and low temperature, where the concentration of N₂O₄ is greatest. The results from varying the stoichiometric ratio of reactants, pressure, temperature, and reaction time in an attempted scale-up of this reaction are consistent with the reaction being equilibrium limited. The best reaction conditions allowed the generation of only 1–3 g of CF₃NO₂ per batch reaction in an approximate 16-L vessel. As long as reaction conditions are chosen so that all of the starting CF₃I is consumed, caustic scrubbing affords a significantly faster, less expensive, and more practical purification method than those previously published.     

Concise synthesis of quinazoline alkaloids, luotonins A and B, and rutaecarpine

The total synthesis of luotonin A was achieved in excellent yield by using a Pd-assisted biaryl coupling reaction of N-(bromoquinolinyl)methylquinazolinone with Cy₃P and KOAc. The successive treatment of luotonin A with NBS and aq. AgNO₃ gave luotonin B in good yield. Although the Pd-assisted coupling reaction of N-(2-bromoindolyl)ethylquinazolinone with Cy₃P and KOAc yielded rutaecarpine in poor yield, N-acetate under the same reaction conditions yielded the desired rutaecarpine directly in excellent yield.     

Bifunctional Onium and Potassium Iodides as Nucleophilic Catalysts for the Solvent-Free Syntheses of Carbonates,Thiocarbonates, and Oxazolidinones from Epoxides

The catalytic potential of organo-onium iodides as nucleophilic catalysts is aptly demonstrated in the synthesis of cyclic carbonates from epoxides and carbon dioxide (CO₂), as a representative CO₂ utilization reaction. Although organo-onium iodide nucleophilic catalysts are metal-free environmentally benign catalysts, harsh reaction conditions are generally required to efficiently promote the coupling reactions of epoxides and CO₂. To solve this problem and accomplish efficient CO₂ utilization reactions under mild conditions, bifunctional onium iodide nucleophilic catalysts bearing a hydrogen bond donor moiety were developed by our research group. Based on the successful bifunctional design of the onium iodide catalysts, nucleophilic catalysis using a potassium iodide (KI)-tetraethylene glycol complex was also investigated in coupling reactions of epoxides and CO₂ under mild reaction conditions. These effective bifunctional onium and potassium iodide nucleophilic catalysts were applied to the solvent-free syntheses of 2-oxazolidinones and cyclic thiocarbonates from epoxides.     

Polymerization of propylene by the three-component system comprising titanium(III) chloride,ethylaluminum sesquichloride,and sodium sulfate

Sodium sulfate increases the polymerization activity of the titanium(III) chloride (AA)–ethylaluminum sesquichloride system for the polymerization of propylene. The reaction of ethylaluminum sesquichloride with sodium sulfate at mild conditions isolates diethylaluminum chloride, which is responsible for the polymerization activity. The reaction of these components at severe conditions forms an organometallic compound containing sulfate, (C₂H₅)₄Al₂SO₄, and this compound is a powerful activator for titanium(III) chloride.     

Azide Ionic Liquids for Safe,Green, and Highly-Efficient Azidation Reactions to Produce Azide Polymers

Azide compounds are widely used and especially, polymers bearing pendant azide groups are highly desired in numerous fields. However, harsh reaction conditions are always mandatory to achieve full azidation, causing severe side reactions and degradation of the polymers. Herein, we report the design and preparation of two azide ionic liquids (AILs) with azide anion and triethylene glycol (E₃)-containing cation, [P_444E3][N₃] and [MIM_E3][N₃]. Compared with the traditional sodium azide (NaN₃) approach, both AILs showed much higher reaction rates and functional-group tolerance. More importantly, they could act as both reagents and solvents for the quantitative azidation of various polymeric precursors under mild conditions. Theoretical simulations suggested that the outstanding performance of AILs originated from the existence of ion pairs during the reaction, and the E₃ moieties played a crucial role. Lastly, after the reaction, the AILs could be easily regenerated, presenting a safer, greener, and highly efficient synthesis route for azide polymers.     

Reaction of 4-Nitrophthalonitrile with Carbonate,Nitrite, and Fluoride

In DMSO and DMF at elevated temperatures, KF, KNO₂, NaNO₂, K₂CO₃, and Na₂CO₃ react with 4-nitrophthalonitrile to form 4,4′-oxybis-(phthalonitrile) and, mostly, 4-hydroxyphthalonitrile. Formation ratios depend on reaction conditions. Intermediates are discussed.     

Microwave synthesis,spectral studies,antimicrobial approach,and coordination behavior of antimony(III) and bismuth(III) compounds with benzothiazoline

The reaction of 2-hydroxy-N-phenylbenzamide with 2-aminobenzenethiol yielded 2-hydroxy-N-phenylbenzamidebenzothiazoline (H₂-Saly · BTZ/HO⋂N⋂SH). The reaction of H₂-Saly · BTZ with PhSbCl₂, SbCl₃, and BiCl₃ under varied reaction conditions (microwave, as well as conventional method) gave corresponding antimony( III) and bismuth(III) Schiff base compounds (substitution along with addition) in different coordination environments. These complexes were characterized by elemental analysis, IR and NMR (¹H and ¹³C) spectral studies. The ligand was found to bifunctional tridentate, as well as monodentate for different starting materials of metal (Sb/Bi), as well as for different reaction conditions, hence, suitable coordination environments and pseudotrigonal bipyramidal geometry for the antimony and bismuth complexes have been proposed. Their biological activities have also been checked against many fungi and bacteria. The complexes were found to be more toxic than the corresponding ligand. The article is published in the original. The article is published in the original.     

Synthesis of the Indene,THF, and Pyrrolidine Skeletons by Lewis Acid Mediated Cycloaddition of Methylenecyclopropanes with Aldehydes,N‐Tosyl Aldimines,and Acetals

Methylenecyclopropanes (MCPs 1 ) react with aldehydes, N‐tosyl aldimines, and acetals to give the corresponding indene, THF, and pyrrolidine cycloaddition products in the presence of BF₃?OEt₂ under mild reaction conditions. Some special transformations of MCPs 1 with aldehydes have been reported in this paper. A plausible reaction mechanism has been discussed, which is based on a deuterium‐labeling experiment and the Prins‐type reaction mechanism.     

A Mild,Simple, Efficient,and Selective Protection of Hydroxyl Groups Using Silica-Supported Sodium Hydrogen Sulfate as a Heterogeneous Catalyst

A mild, simple, novel, and highly efficient method for the rapid protection of various primary, secondary, tertiary aliphatic alcohols, aromatic alcohols, and oximes using hexamethyldisilazane (HMDS) in the presence of silica-supported sodium hydrogen sulfate (NaHSO ₄ -SiO ₂ ), as an active, inexpensive, nontoxic, heterogeneous, and readily available catalyst under ambient conditions is described. Timethylsilyl ethers were prepared in high to excellent yields, with short reaction times under mild and almost neutral reaction conditions at room temperature.     

Mild and Efficient Synthesis of Benzoxazoles, Benzothiazoles, Benzimidazoles, and Oxazolo[4,5-b]pyridines Catalyzed by Bi(III) Salts Under Solvent-Free Conditions

Summary. A series of benzoxazoles, benzothiazoles, benzimidazoles, and oxazolo[4,5-b]pyridines was efficiently synthesized from the reactions of o-aminophenols, o-aminothiophenol, o-phenylenediamines, and 2-amino-3-hydroxypyridine with orthoesters in the presence of catalytic amounts of Bi(III) salts, such as Bi(TFA)₃, Bi(OTf)₃, and BiOClO₄ · xH₂O under solvent-free conditions. The remarkable features of this new protocol are high conversion, very short reaction times, cleaner reaction profiles under solvent-free conditions, straightforward procedure, and use of relatively non-toxic catalysts.     

Supercharged CO2 Photothermal Catalytic Methanation: High Conversion,Rate, and Selectivity

To overcome the thermodynamic and kinetic impediments of the Sabatier CO₂ methanation reaction, the process must be operated under very high temperature and pressure conditions, to obtain an industrially viable conversion, rate, and selectivity. Herein, we report that these technologically relevant performance metrics have been achieved under much milder conditions using solar rather than thermal energy, where the methanation reaction is enabled by a novel nickel-boron nitride catalyst. In this regard, an in situ generated HOB⋅⋅⋅B surface frustrated Lewis's pair is considered responsible for the high Sabatier conversion 87.68 %, reaction rate 2.03 mol g_Ni⁻¹h⁻¹, and near 100 % selectivity, realized under ambient pressure conditions. This discovery bodes well for an opto-chemical engineering strategy aimed at the development and implementation of a sustainable ‘Solar Sabatier’ methanation process.     

Synthesis of Alkenyl Derivatives of Difluoro-, Trifluoro,and Nitroanilines

N-Alkenyl derivatives of di- and trifluoroanilines were prepared by their reaction with 2-chloro-3-pentene. Their transformations under conditions of the Claisen rearrangement were studied. C-Alkenylnitroanilines were prepared by reaction of piperylene with o- and p-nitroanilines in the presence of AlCl₃.     

Simple and Efficient Method for Acetylation of Alcohols,Phenols, Amines,and Thiols Using Anhydrous NiCl2 Under Solvent-Free Conditions

Solvent-free acetylation of alcohols, phenols, amines, and thiols with acetic anhydride (Ac₂O) in the presence of 0.1 mol% (13 mg) anhydrous NiCl₂, an inexpensive and easily available catalyst. Excellent yields, short reaction time, and mild reaction conditions are important features of this method.     

A novel multi-component reaction of indole, formaldehyde, and tertiary aromatic amines

A novel multi-component reaction of indoles, formaldehydes, and tertiary aromatic amines is described for the synthesis of dialkylaminoarylated indoles using silica-supported perchloric acid (HClO₄-SiO₂) as an inexpensive and highly efficient catalyst. The key features of this multi-component reactions are operational simplicity, mild reaction conditions, regioselectivity, and recycling of catalyst.     

Rice husk: A mild,efficient, green and recyclable catalyst for the synthesis of 12-Aryl-8, 9, 10, 12-tetrahydro [a] xanthene-11-ones and quinoxaline derivatives

Rice husk, as a green and cheap reagent, can be used for the promotion of the synthesis of 12-aryl -8, 9,10,12-tetrahydrobenzo[α] xanthen-11-one derivatives (ATXOs) via three-component reaction of aldehydes, 2-naphthol and 5,5-dimethyl-1,3-cyclohexadione (dimedone) under solvent-free conditions. This catalyst can also be used for the preparation of quinoxaline derivatives in a mixture of H₂O and CH₃CN at 50 °C. The present methodology offers several advantages such as high yields, simple procedure, low cost, short reaction times, mild reaction conditions and use of a green, cheap and reusable catalyst.     

The synthesis of bismuth sulfide,antimony sulfide,and their solid solutions from tribenzylbismuth,tribenzylantimony, and elemental sulfur

The condensed phase reactions of tribenzylbismuth or tribenzylantimony and elemental sulfur under mild thermal conditions (≤275°C) produces the respective sesquisulfides in good yields and high purity. A mixture of the perbenzylated metals and elemental sulfur produces solid solutions of the general formula (Bi_xSb_1-x)₂S₃. It has been demonstrated that it is possible to achieve synthetic control over the size and microstructure of the as produced metal sulfide particles by simply changing reaction conditions. In combination with the condensed phase pyrolysis of tris(benzylthiolato)bismuth, five different microstructures for bismuth sulfide are accessible through compounds containing the benzyl ligand.     

Simple and Efficient Method for Acetylation of Alcohols,Phenols, Amines,and Thiols Using Anhydrous NiCl2 Under Solvent-Free Conditions

Solvent-free acetylation of alcohols, phenols, amines, and thiols with acetic anhydride (Ac₂O) in the presence of 0.1 mol% (13 mg) anhydrous NiCl₂, an inexpensive and easily available catalyst, is described. Excellent yields, short reaction time, and mild reaction conditions are important features of this method.     

Solvent-free, ruthenium-catalyzed, regioselective ring-opening of epoxides, an efficient route to various 3-alkylated indoles

Ruthenium-catalyzed regioselective ring-opening of aliphatic and aryl epoxides under solvent-free conditions is reported. It was found that RuCl₃·nH₂O catalyzes the Friedel-Crafts alkylation of indoles, providing 3-alkylated derivatives in good yields under mild reaction conditions.     

Synthesis,structural characterization and alcohol oxidation activity of a new mononuclear manganese(II) complex

A manganese(II) complex of 2,4,6-tris(2-pyridyl)-1,3,5-triazine (tptz) has been synthesized and characterized by single-crystal X-ray diffraction, elemental analyses, IR, and UV–Vis spectroscopic techniques. Oxidation of alcohols to their corresponding aldehydes and ketones was conducted by this catalyst using oxone (2KHSO₅·KHSO₄·K₂SO₄) as an oxidant under biphasic reaction conditions (CH₂Cl₂/H₂O) and tetra-n-butylammonium bromide as phase transfer agent under air at room temperature. Easy preparation, mild reaction conditions, high yields of the products, short reaction times, no further oxidation to the corresponding carboxylic acids, high selectivity and inexpensive reagents make this catalytic system a useful oxidation method for aliphatic and benzylic alcohols.     

Synthesis of α,ω-dimethoxyfluoropolyethers: reaction mechanism and kinetics

A new class of hydrofluoropolyethers, the α,ω-dimethoxyfluoropolyethers (DM-FPEs), characterized by the copolymeric structure CH₃O(CF₂CF₂O)_n(CF₂O)_mCH₃ has been recently developed. The synthesis of DM-FPEs here described, has been carried out via a new synthetic route which consists of the reaction of a perfluoropolyether diacyl fluoride with methyl fluoroformate in the presence of a metal fluoride. The reaction products are DM-FPEs and carbon dioxide.Several reaction conditions has been tested varying type of solvent, temperature, type and amount of metal fluoride. The best results were obtained using tetraglyme as solvent and CsF as metal fluoride.