Ionic liquid-regulated sulfamic acid: chemoselective catalyst for the transesterification of β-ketoesters

Recent advances in the transesterification of β-keto esters

The ability to selectively transesterify β-keto esters is a useful transformation in organic synthesis. The increasing interest in transesterification for the synthesis of compounds of pharmaceutical importance, as well as for biodiesel production, has led to the development of a variety of different approaches. This article aims to summarise recent advances in the transesterifications of β-keto esters. Particular interest has been paid to methodologies with minimal environmental impact.

This review summarises the many advances in the selective transesterification of β-keto esters, with a particular focus on the past 30 years.

Ag–Cu nanoparticles as efficient catalysts for transesterification of β-keto esters under acid/base-free conditions

For the first time transesterification of β-keto esters, conventional acid- or base-catalyzed reactions, has been catalyzed by Ag–Cu bimetallic nanoparticles with high activity.

Sulfamic acid Functionalised Magnetic Nanoparticles: An Efficient Solid Acid for the Multicomponent Condensations

Sulfamic acid-functionalised magnetic nanoparticles have been synthesised and used as efficient heterogeneous solid acid catalysts for the condensation of aromatic aldehydes with 2-naphthol and amides (or carbamates) via three-component reactions under solvent-free conditions at 80°C. Quantitative conversion of the reactants is achieved under mild conditions. Recovery of the catalyst is easily achieved by ‘magnetic decantation’. The supported catalyst is reused four times without any significant degradation in catalytic activity.

One-pot three-component Mannich-type reactions using sulfamic acid catalyst under ultrasound irradiation

Sulfamic acid (NH(2)SO(3)H, SA) was used as an efficient, inexpensive, non-toxic and recyclable green catalyst for the ultrasound-assisted one-pot Mannich reaction of aldehydes with ketones and amines. This ultrasound protocol has advantages of high yield, mild condition, no environmental pollution, and simple work-up procedures. Most importantly, beta-aminocarbonyl compounds with ortho-substituted aromatic amines are obtained in acceptable to good yields by this methodology for the first time.

Sulfamic Acid Catalysed One-Pot Three-Component Condensation for the Synthesis of 1,4-dihydropyrano[2,3-c]pyrazoles

A clean and simple synthesis of 6-amino-4-aryl-3-methyl-1-phenyl-1,4-dihydropyrano[2,3- c]pyrazole-5-carbonitriles was accomplished in good to excellent yields via the one-pot three component condensation of 3-methyl-1-phenyl-2-pyrazolin-5-one, an aromatic aldehyde, and malononitrile catalysed by sulfamic acid in ethanol.

Ultrasound-promoted synthesis of 1-amidoalkyl-2-naphthols via a three-component condensation of 2-naphthol, ureas/amides, and aldehydes, catalyzed by sulfamic acid under ambient conditions

A three-component one-pot condensation of 2-naphthol, ureas/amides and aldehydes catalyzed by sulfamic acid, under ultrasound irradiation and ambient conditions gives 1-amidoalkyl-2-naphthols in excellent yield and in short time.