Synthesis of α,α-Difluoroethyl Aryl and Heteroaryl Ethers

Fluorine plays a critical role in modern medicinal chemistry due to its unique properties, and new methods for its incorporation into target molecules are of high interest. An efficient new method for the preparation of aryl-α,α-difluoroethyl ethers (4) via addition of aryl and heteroaryl alcohols (1) to commercially available 2-bromo-1,1-difluoroethene (2) and subsequent hydrogenolysis is presented. This procedure is an attractive alternative to existing methods that employ harshly reactive fluorinating systems such as xenon difluoride and hydrogen fluoride.     

Triton B–Mediated Efficient and Convenient Alkoxylation of Activated Aryl and Heteroaryl Halides

A simple and convenient one-pot synthesis of aryl alkyl ethers by the alkoxylation of aryl halides with alcohol in the presence of Triton B as a base is described. The procedure is applicable for a variety of aryl and heteroaryl halides, and yields are very good. The use of a nonmetallic base and solvent-free conditions are important features of the reaction.     

Polyethylene Glycol–Enhanced Chemoselective Synthesis of Organic Carbamates from Amines,CO2, and Alkyl Halides

An efficient and environmentally benign method for the synthesis of organic carbamates was developed. Amines, CO₂, and alkyl halides underwent a three-component reaction with the aid of K₂CO₃ and polyethylene glycol (PEG, MW = 400), affording the organic carbamates under ambient conditions. PEG could presumably act as a solvent and phase-transfer catalyst (PTC). Notably, the presence of PEG could also depress the alkylation of both the amine and the carbamate, thus resulting in enhanced selectivity toward the target carbamate.

Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental file.      

Iron(III) Chloride–Promoted Direct Conversion of Aryl/Alkyl Cyanides to Esters

Aryl/alkyl cyanides were quickly converted into the corresponding esters in the presence of iron(III) chloride in refluxing alcohols with very good yields.     

Synthesis and Characterization of Storage Energy Materials Prepared from Nano-crystalline Cellulose/Polyethylene Glycol

The development and the application of phase change materials (PCMs) as a new kind of materials have attracted both scientific and industrial interest1-4. According to the patterns of phase conversion, commonly PCMs are divided into solid-liquid phase cha…     

Solubility of Ketoconazole in Polyethylene Glycol 200 + Water Mixtures at 298.2–318.2 K

The solubility of ketoconazole in binary mixtures of polyethylene glycol 200 (PEG 200) + water is reported at temperatures ranging from 298.2 to 318.2 K. The Jouyban–Acree model and its combined version including the van’t Hoff equation were used for correlating the reported data; the obtained mean relative deviations are 9.5 and 9.9 %, respectively. Also, two previously trained versions of the Jouyban–Acree model were used for predicting the reported data points in which the prediction errors were 34.6 and 31.0 %.     

Copper(Ⅰ)-catalyzed Synthesis of Aryl, Heteroaryl and Vinyl Sulfides in Aqueous Two-phase System

A fast and convenient C―S bond formation reaction was achieved catalyzed by CuI/L-proline in aqueous two-phase system providing a simple method for synthesis of aryl sulfides in good yields in short time.     

Expeditious,Nano-BF3 · SiO2-Catalyzed Michaelis–Arbuzov Reaction in an Ionic Liquid: Synthesis of Privileged Aryl/Heterocyclic Phosphonates

An expeditious, simple, and green method was developed for the synthesis of privileged aryl/heterocyclicphosphonates, 8(a–c) to 13(a–c) through Michaelis–Arbuzov reaction of aryl/heterocyclic halides (Br), 1–6, and trialkylphosphites, 7(a–c), in room-temperature ionic liquid [bbim]Br using heterogeneous Lewis catalyst, nano-silica-supported boron trifluoride (BF₃-SiO₂). The advantages of this protocol are simplicity, good yield of the products, less reaction time (20–38 min), mild reaction conditions, easy workup, and reusability of the catalyst and ionic liquid. It is demonstrated that nano-BF₃-SiO₂ is a recoverable and easy accessible catalyst for the formation of C(sp²)-P bond in an ionic liquid.     

Pentamethylcyclopentadienylruthenium(II) Complexes: Synthesis,Characterization and Catalytic Activity in Aryl–Aryl Coupling

Ruthenium(II) complexes of the type [Ru(PPh₃)( ⁵-C₅Me₅)L] have been synthesized by the reactions of [RuCl(PPh₃)₂( ⁵-C₅Me₅)] with Schiff bases having the (N, O) donor atoms. The Schiff bases used in this study were prepared by condensing the appropriate aniline with salicylaldehyde or 2-hydroxy-1-naphthaldehyde in a 1:2 molar ratio respectively. The complexes were characterized by analytical, spectral (i.r., electronic and ¹H-n.m.r.) data. The new complexes have been used as catalysts in aryl–aryl coupling reactions.     

Synthesis of N-Sulfonylformamidines by tert-butyl Hydroperoxide–Promoted,metal-free,direct oxidative dehydrogenation of aliphatic amines

A direct and convenient metal-free method to prepare sulfonyl amidines in the presence of aqueous tert-butyl hydroperoxide (T-HYDRO) has been developed. Different tertiary and secondary amines were tested for compatibility with the oxidative conditions and could be coupled with sulfonyl azides to form the corresponding amidines in moderate to good yields.     

Efficient Synthesis of β‐Alkyl/Arylsulfanyl Carbonyl Compounds by In‐TMSCl‐Promoted Cleavage of Dialkyl/Diaryl Disulfides and Subsequent Michael Addition

A convenient and efficient procedure for the synthesis of β‐alkyl/arylsulfanyl carbonyl compounds has been developed by a simple one‐pot reaction of dialkyl/diaryl sulfides with α,β‐unsaturated aldehydes, ketones, carboxylic esters, and nitriles in presence of indium and trimethylsilyl chloride under sonication.     

Density,Viscosity, and Glass Transition of an Ethylenediamine–Ethylene Glycol Binary System

Densities ρ and viscosities η were measured for the binary mixtures of ethylenediamine (EDA) and ethylene glycol (EG) in the temperature range 288.15–323.15 K for ρ and at 273.15–323.15 K for η, both of which are broader temperature ranges than those reported previously. The value of ρ monotonously decreases against the mole fraction of EDA, x _EDA, and increasing temperature. The concentration dependence of η exhibits a maximum in the intermediate concentration range at all temperatures measured. The glass transition temperature, T _g, for samples with x _EDA < 0.7 was measured using differential scanning calorimetry. The measured T _g values show a peak in the intermediate concentration range, which is a behavior similar to that of η; however, the peak concentrations for η and T _g did not precisely align because of a deviation in the maximum hydrogen-bond density. The partial molar volumes for EDA and EG and the thermal expansivities, α, were obtained from ρ. Results in the present study are discussed in terms of the extensively increasing hydrogen-bond density for polyamine–polyhydric alcohol systems.     

Copper bis(2,2,6,6-Tetramethyl-3,5-heptanedionate)–Catalyzed Coupling of Sodium Azide with Aryl Iodides/Boronic Acids to Aryl Azides or Aryl Amines

This work reports an efficient protocol for the coupling reaction of aryl iodides/boronic acids with sodium azide to aryl azides/amines in the presence of copper bis(2,2,6,6-tetramethyl-3,5-heptanedionate) Cu(TMHD)₂ catalyst. The Cu(TMHD)₂ catalyst is a structurally well-defined, O-containing, air- and moisture-stable, transition-metal complex and works at mild reaction conditions. It was observed that aryl azides can be reduced further to corresponding aniline derivatives using the same catalyst under basic reaction conditions for a prolonged period.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.]     

Controlling Regioselectivity in Palladium-Catalyzed C−H Activation/Aryl–Aryl Coupling of 4-Phenylamino[2.2]paracyclophane

Selective activation/functionalization of C−H bonds has emerged as an atom- and step-economical process at the forefront of modern synthetic chemistry. This work reports palladium-catalyzed exclusively para-selective C−H activation/aryl–aryl bond formation with a preference over N-arylation under the Buchwald–Hartwig amination reaction of 4-phenylamino[2.2]paracyclophane. This innovative synthetic strategy allows a facile preparation of [2.2]paracyclophane derivatives featuring disparate para-substitutions at C-4 and C-7 positions in a highly selective manner, gives access to a series of potential candidates for [2.2]paracyclophane-derived new planar chiral ligands. The unprecedented behavior in reactivity and preferential selectivity of C−C coupling over C−N bond formation via C−H activation is unique to the [2.2]paracyclophane scaffold compared to the non-cyclophane analogue under the same reaction conditions. Selective C−H activation/aryl–aryl bond formation and sequential C−N coupling product formation is evidenced unambiguously by X-ray crystallography.     

Poly[4-diacetoxyiodo] Styrene–Promoted Thiocyanation of Aromatic Ethers,Anilines, and Indoles

Abstract

Thiocyanation of aromatic ethers, anilines, and indoles have been achieved using ammonium thiocyanate in the presence of poly[4-diacetoxyiodo] styrene (PDAIS) in CH₃CN at room temperature.

GRAPHICAL ABSTRACT     

Volumetric,Acoustic, Viscometric Properties,and Solute–Solvent Interactions of Metformin Hydrochloride in Aqueous Solution of Polyethylene Glycol (PEG 4000) at Different Temperatures (T = 288.15—318.15 K)

Journal of Solution Chemistry - An attempt to understand the interactions between metformin, a drug, and a water-soluble polymer, polyethylene glycol (PEG 4000) in aqueous solutions through...     

Preparation of 5‐Aryl‐3‐Oxo‐δ‐Lactones by the Potassium Carbonate–Promoted Condensation of Aromatic Aldehydes and Ethyl Acetoacetate in Ethanol

5‐Aryl‐3‐oxo‐δ‐lactones (6‐aryl‐dihydro‐2H‐pyran‐2,4(3H)‐diones) were prepared by the potassium carbonate–promoted condensation of aromatic aldehydes and ethyl acetoacetate in absolute ethanol. Benzaldehyde and substituted benzaldehydes bearing an alkoxy group (2 or 3 position), a chlorine atom (2, 3, or 4 position), a nitro group (3 or 4 position), a cyano group (4 position), or an acetyl group (4 position) react in high yields under these conditions.     

Hydrogen Peroxide–Promoted Transformation of Thioureas/Thiosemicarbazides to Related Ureas/Semicarbazides at Room Temperature via Grinding

A novel and environmentally benign synthetic method for ureas through hydrogen peroxide–promoted desulfurization of thioureas at room tepemperature via grinding is reported. As compared with the traditional method, this one is manipulatively simple and the oxidant is low cost, highly active, and environmentally friendly.     

Palladium/PC-Phos-Catalyzed Asymmetric Heck/Tsuji–Trost Reactions of Amino-Tethered 1,3-Cyclohexadiene with Aryl and Alkenyl Halides

Chiral perhydroindoles are found in a number of natural products and biologically active compounds. Therefore, the development of new asymmetric methodology for rapid access to this core is of high importance. Herein, we reported a highly regio- and diastereo-selective palladium/PC-Phos-catalyzed asymmetric Heck/Tsuji–Trost reactions of readily available amino tethered 1,3-cyclohexadienes with aryl and alkenyl halides, delivering various functionalized chiral hexahydroindoles in good yields with high enantioselectivity. The application of this reaction to the concise synthesis of (−)-α-Lycorane was demonstrated. DFT computation results indicate that the difference in ΔE_dis of two migration insertion transition states determines the enantioselectivity of the reaction.     

Ultrasonic Velocities,Densities, and Refractive Indices of Binary Mixtures of Polyethylene Glycol 250 Dimethyl Ether with 1-Propanol and with 1-Butanol

Measurements of the ultrasonic velocity (u), density (ρ) and refractive index (n) for binary mixtures of polyethylene glycol 250 dimethyl ether with 1-propanol and 1-butanol have been made at three temperatures (T=293, 303 and 31 K) over the entire composition range in order to investigate the nature of intermolecular interactions between the components of these liquid mixtures. Various excess thermodynamic properties such as the excess ultrasonic velocity (Δu), deviation in isentropic compressibility (Δk _S ), excess intermolecular free length (L_f^E)(L_{\mathrm{f}}^{\mathrm{E}}), excess acoustic impedance (Z ^E), excess pseudo-Grüneisen parameter (Γ ^E), and molar refraction deviation (ΔR _m) were calculated using experimental values of the ultrasonic velocity, density and refractive index and were then represented with the Redlich-Kister polynomial equation. The observed excess deviation parameter values were explained on the basis of the strength of intermolecular interactions between the components of the mixtures. Estimations of the refractive index and ultrasonic velocity have also been made using various empirical relations and are discussed in terms of the average percentage deviations (APD).