Microwave-assisted synthesis of novel spiro isoxazolidine derivatives

Abstract

α-N-substituted furan derivatives as new dipolarophiles have been employed in 1,3-dipolar cycloaddition reaction with α-chloro nitrones under microwave irradiation and found to afford exclusively novel regioselective 5-spiro cycloadducts with high yield in a very short reaction time.

An efficient,catalyst free synthesis of 3-(2′'-benzothiazolyl)-2,3-dihydroquinazolin-4(1H)-ones in aqueous medium

Abstract

An efficient and environmentally benign protocol for the synthesis of 3-(2′-benzothiazolyl)-2,3-dihydroquinazolin-4(1H)-ones has been developed. The synthesis of these pharmacologically important compounds can be achieved by the three component condensation of isatoic/5-chloroisatoic anhydride, aldehyde, and 2-aminobenzothiazole in water: ethanol (1:1, v/v) without the aid of any catalyst.

A green synthesis of 3,4-dihydropyrimidin-2-ones and 1,5-benzodiazepines catalyzed by Sn(HPO4)2.H2O nanodisks under solvent-free condition at room temperature

Abstract

Heterogeneous Tin (IV) hydrogen phosphate nanodisks [Sn(HPO4)2.H2O] efficiently catalyzed the one-pot three component condensation of aromatic aldehydes, β-ketoesters and urea to produce 3,4–dihydropyrimidin-2-ones under solvent-free conditions at room temperature. Also, the catalyst is equally applicable for the preparation of 1,5–benzodiazepines under the same reaction conditions. The optimum load of the catalyst required is 10 mole% and reusable. Hence, the process is green.

Synthesis of N,N-diallylanilines by the reaction of anilines and allyl bromide in the presence of Mg–Al hydrotalcites at ambient temperature

Abstract

Anilines react with two equivalents of allyl bromide in aqueous ethanol in the presence of Mg–Al hydrotalcites (Mg/Al = 5, 3, 2) at room temperature to give N,N-diallylanilines in good yield. Hydrotalcites (HTs) are mild and efficient catalysts, which can be easily recovered and reused. In this project, efforts are made to check the activity of the calcined and uncalcined HTs. Also, the methodology can be extended for the synthesis of various N,N-diallylanilines.

Synthesis of highly substituted pyrroles using ultrasound in aqueous media

Abstract

A two-step protocol for the synthesis of highly substituted pyrroles in aqueous media and without catalyst is described. The first step is the dimerization of a 1,3-dicarbonyl compound by ceric ammonium nitrate/ultrasound to produce a tetracarbonyl derivative. This derivative is then combined with an amine in the absence of any catalysts to obtain the pyrrole via a Paal–Knorr reaction. This route is an improvement when compared with classical methodologies toward Green Chemistry objectives.

Facile Synthesis of Tetrahydroimidazolpyridinones via an MCR Involving 6-Cl-PMNI,Aldehydes, and Meldrum's Acid

Tetrahydroimidazolpyridinones 2, which are new, highly bioactive potential insecticides, were prepared in 30–96% yield through a multicomponent reaction (MCR) of 6-Cl-PMNI, aldehydes, and Meldrum's acid using catalytic Et₃N or K₂CO₃ in anhydrous CH₃CN at refluxing temperature.