Piperazine: An excellent catalyst for the synthesis of 2-amino-3-cyano-4H-pyrans derivatives in aqueous medium

An ecofriendly, magnetically retrievable amine-functionalized SiO2@Fe3O4 catalyst was successfully synthesized and affirmed by several physicochemical characterization tools, such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FT-IR), vibrating sample magnetometry (VSM), energy-dispersive X-ray spectroscopy (EDX), and powder X-ray diffraction. Thereafter, the catalytic performance of this environmentally benign NH2@SiO2@Fe3O4 catalyst was investigated in the one-pot multicomponent synthesis of 2-amino-4H-benzo[b]pyran derivatives. The reaction was simply achieved by grinding of various substituted aromatic aldehydes, dimedone, and malononitrile at room temperature under solvent and waste-free conditions with excellent yields and high purity. Moreover, the developed catalyst not only possesses immense potential to accelerate the synthesis of bioactive pyran derivatives but also exhibits several remarkable attributes like broad functional group tolerance, durability, improved yield, reusability, and recyclability. Besides, various other fascinating advantages of this protocol are milder reaction conditions, cost effectiveness, short reaction time, and simple work up procedures.

https://pubs.acs.org/doi/pdf/10.1021/acsomega.9b04117

Green and Mechanochemical One-Pot Multicomponent Synthesis of Bioactive 2-amino-4H-benzo[b]pyrans via Highly Efficient Amine-Functionalized SiO2@Fe3O4 Nanoparticles.

Synthesis of heterocyclic compounds via Michael and Hantzsch reactions

In this review, we tried to underscore the synthesis of the heterocyclic compounds under assisted ultrasonic irradiation. The ultrasonic irradiation has been applied for medicinal chemistry and drug discovery process since it dramatically reduces reaction times, from days or hours to minutes. Also, ultrasonic irradiation provides lower cost, excellent yields, greater purity, and simple workups as compared to lower yields, longer reaction times, lesser purity and in the conventional methods. In this review, we have compared synthesis of the heterocyclic compounds under ultrasonic irradiation with other methods.

Ultrasound-assisted synthesis of heterocyclic compounds

Magnetized melamine-modified polyacrylonitrile (PAN@melamine/Fe3O4) organometallic nanomaterial: Preparation, characterization, and application as a multifunctional catalyst in the synthesis of bioactive dihydropyrano [2,3-c]pyrazole and 2-amino-3-cyano 4H-pyran derivatives

A convenient one-pot multi-component strategy was conducted successfully under catalyst-free conditions employing water and PEG-400 as the efficient and cheap promoting medium. Three types and nearly 50 2-amino-3-cyano-4H-pyran annulated derivatives were synthesized in good to excellent yields by the condensation of a series of aromatic aldehydes with malononitrile and different 1,3-dicarbonyl compounds. Broad substrate scope, systematic characterization, eliminated catalyst, brief reaction time, and simple purification procedure are the best merits in this process.

Fei Li

Papers

Efficient synthesis of 2-amino-3-cyano-4H-pyran derivatives via a non-catalytic one-pot three-component reaction