Ultrasound-promoted alkynylation of ethynylbenzene to ketones under solvent-free condition

Sonochemical one pot synthesis of novel spiroacridines catalyzed by magnetically functionalized Fe3O4 nanoparticles with chitosan as a reusable effective catalyst

Fe₃O₄@CS–SO₃H NPs low toxicity, easy preparation, recyclable catalyst for the synthesis of spiroacridine in aqueous ethanol is reported.

Ultrasound-promoted one-pot five-components synthesis of biologically active novel bis((6-alkyl or phenyl-2-phenylpyrimidine-4-yl) oxy) alkane or methyl benzene derivatives

We have described a synthesis of novel five-component reaction (5-CR) of bis((6-alkyl or phenyl-2-phenylpyrimidine-4-yl) oxy) alkane or methyl benzene derivatives under ultrasound irradiation. A useful ultrasound effect was observed and title products were obtained with high yields after 25-40 min sonication. Structural confirmation and characterization of the products based on the analytical, chemical, and spectral analysis. The results show obviously, that to reach a high efficiency of ultrasonic systems in synthetic chemical processes. Our procedure compared to the conventional heating method has the benefit of higher reaction yields and shorter reaction times. The in vitro antibacterial tests show that some of the target compounds have promising activities. Structure-activity relationships (SAR) were established for the substitutions on the pyrimidine rings and related length of linear chain linker.

Ultrasound-mediated synthesis of N,N-bis(phenacyl)aniline under solvent-free conditions

Abstract

An efficient method for the synthesis of N,N-bis(phenacyl)anilines was developed via smooth condensation of anilines with α-bromoacetophenones in the presence of sodium carbonate as acid acceptor and polyethylene glycol 400 (PEG 400) as catalyst at room temperature under solvent-free conditions by using 350 W ultrasound irradiation. In addition to experimental simplicity, the main advantages of the procedure are mild conditions, short reaction times (30–45 min), and high yields (73–83 %).

Graphical Abstract

Ultrasound-promoted one-pot, three-component synthesis of spiro[indoline-3,1'-pyrazolo[1,2-b]phthalazine] derivatives

A series of 3'-aminospiro[indoline-3,1'-pyrazolo[1,2-b]phthalazine]-2,5',10'-trione derivatives have been synthesized by a one-pot three-component reaction of isatin, malononitrile or ethyl cyanoacetate and phthalhydrazide catalyzed by piperidine under ultrasound irradiation. For comparison the reactions were carried out under both conventional and ultrasonic conditions. In general, improvement in rates and yields were observed when the reactions were carried out under sonication compared with classical conditions.

A novel and convenient synthesis of 4-hydroxy-6-methyl-3-(1-(phenylimino) ethyl)-2H-pyran-2-one derivatives under ultrasound irradiation

A facile, efficient and environment-friendly protocol for the synthesis of 4-hydroxy-6-methyl-3-(1-(phenylimino)ethyl)-2H-pyran-2-one derivatives has been developed by the convenient ultrasound-mediated condensation of amine with dehydroacetic acid. This method provides several advantages over current reaction methodologies including a simple work-up procedure, shorter reaction times and higher yields.

A convenient ultrasound-promoted regioselective synthesis of fused polycyclic 4-aryl-3-methyl-4,7-dihydro-1H-pyrazolo[3,4-b]pyridines

Fused polycyclic 4-aryl-3-methyl-4,7-dihydro-1H-pyrazolo[3,4-b]pyridines were obtained in a three-component regioselective reaction of 5-amino-3-methyl-1H-pyrazole, 2H-indene-1,3-dione and arylaldehydes in ethanol under ultrasound irradiation. This rapid method produced the products in short reaction times (4-5min) and excellent yields (88-97%).

An efficient ultrasound-promoted synthesis of the Baylis-Hillman adducts catalyzed by imidazole and L-proline

A convenient protocol was developed for the synthesis of the Baylis-Hillman adducts in the presence of weak Lewis base and l-proline at room temperature under ultrasound irradiation. This method provided the products in good to high yields (65-90%) and reasonable reaction times.