A facile one-pot ultrasound assisted for an efficient synthesis of 1H-spiro[furo[3,4-b]pyridine-4,3'-indoline]-3-carbonitriles

Silver nanoparticles-decorated Preyssler functionalized cellulose biocomposite as a novel and efficient catalyst for the synthesis of 2-amino-4H-pyrans and spirochromenes

Silver nanoparticles-decorated Preyssler functionalized cellulose biocomposite (PC/AgNPs) was prepared and fully characterized by FTIR, UV–vis, SEM, and TEM techniques. The preparation of PC/AgNPs was studied systematically to optimize the processing parameters by Taguchi method using the amount of PC, reaction temperature, concentration of silver nitrate and pH of medium. Taguchi’s L9 orthogonal (4 parameters, 4 level) was used for the experimental design. The SEM analysis confirmed the presence of the Preyssler as a white cloud as well as spherical AgNPs on the surface of cellulose. The formation of AgNPs on the surface was observed by changing of the color from yellow to deep brown and confirmed by UV–vis spectroscopy. The best yield of AgNPs forming was obtained in pH 12.5 at 80 ºC in 20 min. TEM analysis confirmed the formation of spherical AgNPs with a size of 50 nm, at the 1% wt. loading of Preyssler. This easily prepared PC/AgNPs was successfully employed as an efficient, green, and reusable catalyst in the synthesis of a wide range of 2-amino-4H-pyran and functionalized spirochromene derivatives via a one-pot, multicomponent reaction. The chief merits realized for this protocol were the utilization of commercially available or easily accessible starting materials, operational simplicity, facile work-up procedure, obtaining of high to excellent yields of the products and being done under green conditions. The catalyst could be easily separated from the reaction mixture and reused several times without observing any appreciable loss in its efficiency.

Synthesis of Spiro1,4-Dihydropyridines: A Review

The preparation of medicinally promising spiro1,4-dihydropyridines accompanied by their applications in biological and pharmaceutical activities is presented. Spiro1,4-dihydropyridines were synthesized using numerous reported methods including bronested acids such as p-TSA, AcOH, nano-ranged calix[4]arene tetracarboxylic acid, sulfamic acid, PEG-OSO3H, tetramethylguanidinium triflate; lewis acids including Zn(OTf)2, FeCl3, copper, alum, aluminosilicate nanoparticles, MnFe2O4 nanoparticles, manganese ferrite nanoparticles, BF3OEt2; under alkaline conditions such as Et3N and piperidine; ionic liquids such as [KAl(SO4)2·12H2O] and [Bmim]PF6, [MIM(CH2)4SO3H][HSO4]; and other miscellaneous procedures, for example, microwave-assisted catalyst and solvent-free conditions, using iodine, PEG-400, and NaCl.

Ultrasound promoted facile one pot synthesis of triazole derivatives catalyzed by functionalized graphene oxide Cu(I) complex under mild conditions

A facile one pot three component reaction of alkyl halides, sodium azide with terminal alkynes can be catalyzed by functionalized graphene oxide copper (I) complex under ultrasonic irradiation at room temperature. In this protocol, the 1,4-disubstituted 1,2,3-triazoles were afforded as target pure products in excellent yields and short reaction times. The prepared catalyst has been characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction spectroscopy (XRD), Energy Dispersive X-ray (EDX) and field emission scanning electron microscopy (FE-SEM) techniques. Also, the catalyst is chemoselective and stable and can be reused several times without any appreciable loss of its catalytic activity.

Efficient sonochemical green reaction of aldehyde, thiobarbituric acid and ammonium acetate using magnetically recyclable nanocatalyst in water

A facile one-pot and four-component economical synthesis of pyrido[2,3-d:6,5-d]dipyrimidines using aldehyde, 2-thiobarbituric acid and ammonium acetate in the presence of magnetically heterogeneous catalyst under ultrasonic irradiation in water is described. The present synthesis shows attractive characteristics such as; the use of magnetically recoverable and reusable catalyst, convenient one-pot operation, short reaction periods, high to excellent yields and the use of water as a green reaction medium, mild reaction conditions and is considered to be relatively environmentally benign.

An efficient, one-pot three-component synthesis of 4H-thiazolo[3,2-a][1,3,5]triazin-6-one derivatives

A simple and efficient protocol was established to synthesize thiazolo[3,2-a][1,3,5]triazin-6-ones via three-component one-pot condensation reaction of readily available thioglycolic acid or ethyl thioglycolate, aldehydes or ketones and dicyandiamide in the presence of ammonium acetate. All of the newly synthesized compounds were characterized by spectroscopic analyses.

Ultrasound-promoted one-pot three component synthesis of tetrazoles catalyzed by zinc sulfide nanoparticles as a recyclable heterogeneous catalyst

Ultrasound irradiation was applied for the appropriate and rapid synthesis of 1-substituted tetrazoles through cyclization reaction of various primary amines, sodium azide and triethyl orthoformate. This reaction was effectively catalyzed by ZnS nanoparticles as an efficient, recoverable and reusable catalyst. Compared with conventional methods, this method has the considerable advantages such as shorter reaction times, easier work-up, purer products with high yields and mild conditions. The ZnS nanoparticles catalyst is an excellent instance to replace Brønsted acids for the preparation of 1-substituted tetrazole derivatives in very short reaction times with excellent yields. The catalyst can be recovered and reused several times without significant loss of its catalytic activity.

Efficient synthesis of functionalized spiro[indoline-3,4′-pyridines] and spiro[indene-2,4′-pyridines] via a three-component reaction

Three-component reactions for the synthesis of polysubstituted spiro[indoline-3,4′-pyridines] and spiro[indene-2,4′-pyridines] in good yields and with high diastereoselectivity.