On the nonlinear dynamical systems within the generalized fractional derivatives with Mittag–Leffler kernel

Nonlinear Dynamics - The purpose of this paper is to study the existence and uniqueness of the solution of nonlinear fractional differential equations with Mittag–Leffler nonsingular kernel....     

Iron‐catalyzed cross‐coupling reaction: Heterogeneous palladium and copper‐free Heck and Sonogashira cross‐coupling reactions catalyzed by a reusable Fe(III) complex

An interesting silica‐supported iron catalyst was successfully prepared and demonstrated as an efficient heterogeneous catalyst for cross‐coupling reactions of aryl halides. The as‐prepared nanocatalyst was well characterized and found to be highly efficient in Heck reaction under mild and sustainable conditions (water as solvent at 80 °C in short reaction time). Furthermore, the obtained catalyst was used as an efficient, inexpensive and green heterogeneous catalyst for Sonogashira cross‐coupling reactions of various aryl iodides and provided the corresponding products with moderate to good yields. This phosphine, copper and palladium‐free catalyst was simply recovered from the reaction mixture and recycled five times without substantial decrease in its catalytic activity.     

Application of a dimeric ortho‐palladated complex of tribenzylamine as an efficient catalyst in microwave‐assisted Hiyama coupling reactions

The activity of [Pd{C₆H₄(CH₂N(CH₂Ph)₂)}(μ‐Br)]₂ complex was investigated in cross‐coupling reactions of triethoxy(phenyl)silane with various aryl halides under microwave irradiation. This complex is an efficient and stable catalyst for the synthesis of substituted biphenyls that is non‐sensitive to air and moisture. The combination of dimeric complex as homogenous catalyst, microwave irradiation, DMF as microwave‐active polar solvent and TBAF as microwave‐active additive led to excellent yields in short reaction times. Copyright © 2012 John Wiley & Sons, Ltd.     

Choline chloride/CuCl as an effective homogeneous catalyst for palladium-free Sonogashira cross-coupling reactions

Choline chloride–CuCl (ChCl–CuCl) has been employed as an efficient catalytic system in the palladium-free Sonogashira-type cross-coupling reactions of phenylacetylene with a variety of aryl halides. Choline chloride, as an effective ligand and a quaternary ammonium salt, demonstrated an efficient stabilizing effect on the Cu(I) species during the reaction. This homogeneous catalytic system is attractive in view of its ease of application and low cost.     

Simple and Facile Tetrahydropyranylation of Alcohols by use of Catalytic Amounts of Benzyltriphenylphosphonium Tribromide

An efficient and mild system for protection of a variety of alcohols with 3,4‐dihydro‐2H‐pyran (DHP) in the presence of catalytic amounts of benzyltriphenylphosphonium tribromide (BTPTB) (1) gives the corresponding tetrahydropyan ethers (ROTHP) in dichloromethane. The experimental procedure is simple, and the products are straightforwardly isolated in high to excellent yields.     

An Easy and Efficient Method for Cleavage of Carbon-Nitrogen Double Bonds Under Non-Aqueous and Neutral Conditions

1-Benzyl-4-aza-1-azoniabicyclo[2.2.2]octane periodate (BAABCP) (1), readily prepared as an orange solid from commercially available DABCO (1,4-diazabicyclo [2.2.2]octane, performs oxidation in anhydrous conditions. Under these conditions, the reagent converts phenylhydrazones, p-phenylhydrazones, semicarbazones, and β-keto sulfoxide hydrazones to the corresponding carbonyl compounds and β-keto sulfoxides respectively, the yields and enantioselectivity are excellent.     

Oxidation of Benzylic Alcohols to Their Corresponding Carbonyl Compounds using KIO4 in Ionic Liquid by Microwave Irradiation

A chemoselective, straightforward, and rapid method for oxidation of alcohols to the corresponding carbonyl compounds using microwave irradiation and a catalytic amount of ionic liquid is reported. The reaction has been carried out with excellent yields and short reaction times.     

Triphenylmethylphosphonium Dichromate: An Effective and Chemoselective Reagent for Oxidation of Benzylic Alcohols to the Corresponding Aldehydes and Ketones

An efficient and straightforward method for oxidation of the benzylic alcohols to the corresponding aldehydes and ketones has been accomplished using triphenylmethylphosphonium dichromate (MTPPD) under solvent-free conditions with high chemoselectivity. The reaction is fast with good yields and straightforward workup.     

Synthesis of 1,2,4,5-tetrasubstituted imidazoles and 2,4,5,6-tetrasubstituted pyrimidines: three-component,the one-pot reaction of arylamidines,malononitrile, and arylglyoxals or aryl aldehydes

A highly efficient one-pot synthesis of the 1,2,4,5-tetrasubstituted imidazoles and 2,4,5,6-tetrasubstituted pyrimidines through an arylamidine, malononitrile, and carbonyl compound by using Et₃N in CH₃CN at reflux conditions was developed. The nature of the carbonyl compounds were different; when the carbonyl compound was arylglyoxal or aryl aldehyde, 1,2,4,5-tetrasubstituted imidazole and 2,4,5,6-tetrasubstituted pyrimidine were achieved respectively.