Efficient synthesis of 2,3-disubstituted-2,3-dihydroquinazolin-4(1H)-ones catalyzed by dodecylbenzenesulfonic acid in aqueous media under ultrasound irradiation.

Synthesis of 2,3-disubstituted-2,3-dihydroquinazolin-4(1H)-one derivatives catalyzed by dodecylbenzenesulfonic acid was carried out in 80-92% yields at 40-42 °C within 1-2 h in aqueous media via one-pot three-component condensation of isatoic anhydride, aromatic aldehyde and amine under ultrasound irradiation. Convenient work-up procedures, mild reaction conditions, avoiding the use of organic solvents, and friendly to environment are the salient features of this protocol.

An efficient synthesis of 2-substituted benzothiazoles in the presence of FeCl3/Montmorillonite K-10 under ultrasound irradiation.

2-Substituted benzothiazoles have been synthesized via one-pot reaction from aromatic aldehydes and o-aminothiophenol in the presence of FeCl(3)/Montmorillonite K-10 in absolute methanol at 25-30°C under ultrasound irradiation. The remarkable advantages are an inexpensive and easily available reagent, a simple procedure, mild conditions, short reaction times and moderate to good yields.

Degradation of naproxen by combination of Fenton reagent and ultrasound irradiation: optimization using response surface methodology.

A central composite factorial design methodology was employed to optimize the degradation of naproxen (NPX) by the combination of Fenton reagent and ultrasound (US) irradiation. In this study, the variables considered for the process optimization were the hydrogen peroxide, ferrous ion and NPX initial concentrations, while ultrasonic power amplitude was adjusted at 90% and initial pH was 3. An appropriate quadratic model was developed in order to plot the response surface and contour curves. Optimum dosage of Fenton reagent for NPX removal was found to be hydrogen peroxide concentration = 9.98 mmol L⁻¹, ferrous ion concentration = 4.83 mg L⁻¹ while NPX concentration was equal to 20 mg L⁻¹. A degradation efficiency of 100% was achieved within 10 min under US.

Synthesis of 2-(1,5-diaryl-1,4-pentadien-3-ylidene)-hydrazinecarboximidamide hydrochloride catalyzed by p-dodecylbenzenesulfonic acid in aqueous media under ultrasound irradiation.

Amidinohydrazone compounds are very important synthetic intermediates and can serve as versatile precursors in synthesis of many natural products and drug molecules. The use of ultrasound, p-dodecylbenzenesulfonic acid (DBSA) and water as solvent improved the synthesis of different 2-(1,5-diaryl-1,4-pentadien-3-ylidene)-hydrazinecarboximidamide hydrochlorides. The best reaction conditions for the condensation of 1,5-diphenyl-1,4-pentadien-3-one with aminoguanidine hydrochloride were as follows: 1,5-diphenyl-1,4-pentadiene-3-one (1, 1 mmol), aminoguanidine hydrochloride (1.1 mmol), DBSA (0.5 mmol), water 10 mL, reaction temperature 25-27°C, irradiation frequency 25 kHz. 2a was achieved in 94% yield within 2h. The other seven amidinohydrazones were obtained in 84-94% yield within 2-3h under the same conditions. Compared to the method involving catalysis by hydrochloric acid in refluxing EtOH, the advantages of present procedure are milder conditions, shorter reaction times, higher yields, and environmental friendly conditions, which make it a useful strategy for the synthesis of analogues.

Improved synthesis of 2,2'-arylmethylene bis(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one) derivatives catalyzed by urea under ultrasound.

Synthesis of 2,2'-arylmethylene bis(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one) derivatives catalyzed by urea via the condensation of aromatic aldehydes and 5,5-dimethyl-1,3-cyclohexanedione was carried out in 80-98% yields at 50 °C in aqueous media under ultrasound. This method provides several advantages such as environment friendliness, high yields and simple work-up procedure.

Efficient one-pot three-component synthesis of N-(4-arylthiazol-2-yl) hydrazones in water under ultrasound irradiation.

A highly efficient and facile one-pot three-component synthesis of N-(4-arylthiazol-2-yl) hydrazones was carried out in excellent yield without any catalyst in water under ultrasound irradiation.

Efficient and green synthesis of bis(indolyl)methanes catalyzed by ABS in aqueous media under ultrasound irradiation.

Ultrasound-promoted synthesis of bis(indolyl)methanes catalyzed by ABS via the reaction of indole or N-methylindole with aromatic aldehyde was carried out in excellent yields in aqueous media at 23-25°C, providing a simple and efficient synthesis of these compounds.

Improved synthesis of 3-(dialkylaminomethyl)-indole in acetic acid aqueous solution under ultrasound irradiation.

Synthesis of Mannich bases related to gramine via Mannich reaction of secondary amine, formaldehyde and indole or N-methylindole can be carried out in 69-98% yields in acetic acid aqueous solution at 35°C under ultrasound irradiation. Compared with the method using stirring, the present procedure provided several advantages such as milder conditions, shorter reaction time and higher yield.

An efficient one-pot synthesis of 2,3-epoxyl-1,3-diaryl-1-propanone directly from acetophenones and aromatic aldehydes under ultrasound irradiation.

A convenient and efficient one-pot synthesis of 2,3-epoxyl-1,3-diaryl-1-propanone directly from acetophenones and aromatic aldehydes under ultrasound irradiation at room temperature has been described. In comparison to two-step methods, the present procedure has the advantages of mild conditions, shorter reaction time, without isolation of any intermediate, saves energy and no requirement of toxic solvent.

Ultrasound promoted efficient method for the cleavage of 3-aryl-2,3-epoxyl-1-phenyl-1-propanone with indole.

An efficient synthesis of 3-aryl-3-hydroxy-2-(1H-indol-3-yl)-1-phenyl-1-propanone via the cleavage of epoxides with indole promoted by ultrasound irradiation was carried out in good yields by using montmorillonite K10-ZnCl(2) within 2-5h at room temperature. This method provides several advantages such as operational simplicity, high yield and mild conditions.

A convenient and efficient protocol for the synthesis of 5-aryl-1,3-diphenylpyrazole catalyzed by hydrochloric acid under ultrasound irradiation.

The synthesis of 5-aryl-1,3-diphenylpyrazole via the reactions of 3-aryl-2,3-epoxy-1-phenyl-1-propanone with phenylhydrazine was carried out in 69-99% yields at room temperature under ultrasound irradiation. This method provides several advantages such as operational simplicity, higher yield and environment friendly.

An efficient deprotection of oximes to carbonyls catalyzed by silica sulfuric acid in water under ultrasound irradiation.

Deprotection of oximes to the corresponding carbonyl compounds in silica sulfuric acid/surfactant/paraformaldehyde system can be carried out in excellent yields at 50 degrees C in water under ultrasound irradiation.

Synthesis of glycoluril catalyzed by potassium hydroxide under ultrasound irradiation.

Synthesis of the glycolurils catalyzed by potassium hydroxide was carried out in 17-75% yield at 40 degrees C in EtOH under ultrasound irradiation. Compared to the method using stirring, the main advantage of the present procedure is milder conditions and shorter reaction time.

Ultrasound promoted one-pot synthesis of 3-aza-6,10-diaryl-2-oxa-spiro[4.5]decane-1,4,8-trione.

One-pot synthesis of 3-aza-6,10-diaryl-2-oxa-spiro[4.5]decane-1,4,8-trione from 1,5-diaryl-1,4-pentadien-3-one can be carried out in good yields at 50 degrees C under ultrasound irradiation. This method provided several advantages such as simple work-up procedure, shorter reaction time and higher yield.

Degradation of C.I. Direct Black 168 from aqueous solution by fly ash/H2O2 combining ultrasound.

Degradation of C.I. Direct Black 168 from aqueous solution using Fenton-like reactions combining ultrasound was investigated. In the presence of H(2)O(2), the effect of the heterogeneous catalysts, such as fly ash, kaolinite or diatomaceous earth on the degradation of Direct Black 168 was observed under ultrasound. The fly ash was the most efficient catalyst. It is apparent that ultrasound can prompt the reaction to take place and give in higher degradation. In the combination of ultrasound and fly ash/H(2)O(2), the effect of different system variables namely concentration of the dye, dosage of fly ash, concentration of H(2)O(2), pH of solution and the addition of NaCl were studied. 99.0% removal ratio was achieved at initial concentration 100mg/L, pH 3.0, and dosage of fly ash 2.0 g/L, as well as 2.94 mM H(2)O(2). NaCl exhibited only a minor effect on the dye removal.

Oxidative cleavage of hydrobenzoin by ACC/silica gel under ultrasound irradiation.

A mild and efficient method has been developed using ultrasound irradiation for oxidative cleavage of hydrobenzoin with ACC/silica gel in dichloromethane. A high yield of 72-99% has been obtained for the oxidation of a series of hydrobenzoins into aromatic aldehydes at room temperature.

An efficient oxidation of benzoins to benzils by ACC/silica gel under ultrasound irradiation.

The oxidation of benzoins to the corresponding benzils was carried out in CH2Cl2 by ACC/silica gel in excellent yields within short time under ultrasound irradiation.

One-pot synthesis of benzylacetamide from oxime under ultrasound irradiation.

One-pot synthesis of benzylacetamide from oxime can be carried out in 80-95% yield at 35-40 degrees C under ultrasound irradiation. This method provided several advantages such as simple work-up procedure, shorter reaction time and higher yield.

The solvent-free synthesis of 1,4-dihydropyridines under ultrasound irradiation without catalyst.

The condensation of aldehydes, ethyl acetoacetate and ammonium acetate result 1,4-dihydropyridines in 82-99% yields under ultrasound irradiation without solvent and catalyst at room temperature. Compared with conventional methods, the main advantages of the present procedure are milder conditions, shorter reaction time and higher yields.

An efficient and practical synthesis of 2-((1H-indol-3-yl)(aryl)methyl)malononitriles under ultrasound irradiation.

Synthesis of 2-((1H-indol-3-yl)(aryl)methyl)malononitrile via the Michael addition of indole with various arylmethylenemalononitriles was carried out in good yields using anhydrous zinc chloride as the catalyst under ultrasound irradiation.