Hongjun Zang

Ionic liquid [EMIM]OAc under ultrasonic irradiation towards the first synthesis of trisubstituted imidazoles.

The ionic liquid 1-ethyl-3-methylimidazole acetate ([EMIM]OAc) was found to be a mild and effective catalyst for the efficient, one-pot, three-component synthesis of 2-aryl-4,5-diphenyl imidazoles at room temperature under ultrasonic irradiation. This procedure has many obvious advantages compared to those reported in the previous literatures, including avoiding the use of harmful catalysts, reacting at room temperature, high yields, simplicity of the methodology.

Ultrasound-promoted synthesis of oximes catalyzed by a basic ionic liquid [bmIm]OH.

The basic ionic liquid 1-butyl-3-methylimidazolium hydroxide, [bmIm]OH, efficiently catalyzes the condensation reaction of aldehydes and ketones with hydroxylamine hydrochloride under ultrasound irradiation. Compared with conventional methods, the main advantages of the present procedure are milder conditions, shorter reaction time and higher yields.

An efficient ultrasound-promoted method for the one-pot synthesis of 7,10,11,12-tetrahydrobenzo[c]acridin-8(9H)-one derivatives

A new, efficient and general method for preparation of 7,10,11,12-tetrahydrobenzo[c]acridin-8(9H)-one derivatives using ultrasound irradiation is reported. Under ultrasound, the reaction time is short, the yields are high and the reaction conditions are mild.

Ionic liquid under ultrasonic irradiation towards a facile synthesis of pyrazolone derivatives.

Ionic liquid [HMIM]HSO(4) was found to be an efficient catalyst for the synthesis of 4-[(5-hydroxy-3-methyl-1-phenyl-1H-pyrazol-4-yl)-phenyl-methyl]-5-methyl-2-phen-yl-1,2-dihydro-pyrazol-3-ones through the condensation reaction of arylaldehydes and 3-methyl-1-phenyl-5-pyrazolone under ultrasonic irradiation at room temperature. The present methodology offers several advantages such as excellent yields, simple procedure and mild conditions.

1-Methylimidazolium hydrogen sulfate catalyzed convenient synthesis of 2,5-dimethyl-N-substituted pyrroles under ultrasonic irradiation

Ionic liquid [HMIM]HSO4 was found to be an efficient catalyst for the synthesis of N-substituted pyrroles through the reaction of 2,5-hexanedione with amines under ultrasonic irradiation at room temperature. These reactions proceed with good yields under short reaction time. Furthermore, the green catalytic system can be recycled specific times with no decreases in yields and reaction rates.

Ultrasound-Promoted One-Pot Synthesis of 7-Aryl-7,10,11,12-tetrahydrobenzo[c]acridin-8(9H)-one Derivatives

Abstract A series of 7-aryl-7,10,11,12-tetrahydrobenzo[c]acridin-8(9H)-one derivatives were synthesized via the three-component coupling from aromatic aldehydes, 1-naphthylamine, and 5,5-dimethylcyclohexane-1,3-dione catalyzed by stannous chloride dihydrate (SnCl2 · 2H2O) under ultrasonic irradiation at room temperature. The products were isolated in good yields within short reaction times.

Direct conversion of chitosan to 5-hydroxymethylfurfural in water using Brønsted–Lewis acidic ionic liquids as catalysts

The dehydration of chitosan to 5-hydroxymethylfurfural (HMF) via hydrothermal conversion was investigated in the presence of Bronsted–Lewis acidic ionic liquids. The catalytic effect of different Bronsted- and Lewis-acidic sites and the molar fraction of Lewis-acidic sites were investigated in detail. It was found that Bronsted–Lewis acidic ionic liquids ([Hmim][HSO4]–0.5FeCl2) exhibited good catalytic performance, furnishing HMF in 44.11% yield. Furthermore, the effects of reaction temperature, time, and amount of catalyst were also investigated. The optimal reaction conditions were obtained for a 1.25 wt% aqueous solution of the catalyst under hydrothermal conditions (180 °C for 4 h). A high HMF yield of 44.11% was obtained starting from 50 mg of chitosan. The Bronsted–Lewis acidic ionic liquid catalysts could be recycled by simple separation and exhibited constant activity in four successive trials.

Recyclable montmorillonite-supported thiazolium ionic liquids for high-yielding and solvent-free upgrading of furfural and 5-hydroxymethylfurfural to C10 and C12 furoins

Six Na+/montmorillonite (MMT) – supported thiazolium (TM) ionic liquids (ILs), MMT–[TM], which are precatalysts to N-heterocyclic carbene (NHC) catalysts, have been synthesized and employed to catalyze the highly selective condensation of furfural (FF) and 5-hydroxymethylfurfural (HMF) into C10 and C12 furoins, respectively. Among them, five supported [TM] salts carrying the electron-donating group exhibit excellent catalytic activity. Thus, supported NHC catalysts, generated in situ from activation of MMT–[TM] with Et3N, afford C10 and C12 furoins in 97–99% and 97–98% yield, respectively. This condensation reaction is also carried out under solvent-free conditions, and the catalysts can be readily recycled, showing no noticeable loss in their catalytic activity over four consecutive recycles. Thus, these desired features possessed by the current catalyst system have enabled the development of the greener and more environmentally benign process for the upgrading of FF and HMF.

3,3,6,6-Tetra­methyl-9-(2-nitro­phen­yl)-3,4,6,7-tetra­hydro-2H-xanthene-1,8(5H,9H)-dione

In the title compound, C23H25NO5, the pyran ring adopts a flattened boat conformation, while the two cyclohexenone rings are in envelope conformations. The 3-nitrophenyl ring is almost perpendicular to the pyran ring, making a dihedral angle of 87.1 (3)°.

An efficient method for synthesis of 3-arylbenzo[f]quinoline-1,2-dicarboxylates catalyzed by SnCl2

A wide variety of 3-arylbenzo[f]quinoline-1,2-dicarboxylates and their dehydro derivatives have been synthesized by one-pot, three-component reaction of an aromatic aldehyde, naphthalene-2-amine, and dimethyl but-2-ynedioate in the presence of SnCl2 under reflux in acetonitrile. This procedure has several advantages, for example high yield, short reaction time, easy work-up, little pollution, and low price of the catalyst.