Multicomponent Reactions of 1,3‐Cyclohexanediones and Formaldehyde in Glycerol: Stabilization of Paraformaldehyde in Glycerol Resulted from using Dimedone as Substrate

Abstract

Glycerol has proved to be an effective promoting medium for many multicomponent reactions of 1,3-cyclohexanediones and formaldehyde. Styrenes, amines, 2-naphthol, 4-hydroxy-6-methyl-2-pyrone and 4-hydroxy-1-methyl-2-quinolone could easily react with 1,3-cyclohexanediones and paraformA C H T U N G T R E N N U N G aldehyde in glycerol under catalyst-free conditions to afford a variety of complex skeletons in fair to excellent yields. In these reactions, glycerol not only showed a significant promoting effect on the reaction yields but also endowed the reaction system with many typical properties of green chemistry, such as cheap, renewable, recyclable and biodegradable solvent, good safety and easy separation of product. The promoting effect of glycerol for the three-component reaction of styrene, dimedone and paraformA C H T U N G T R E N N U N G aldehyde could be attributed to a restricted formation of the methylene intermediate in glycerol. During the reaction, a physical shell, which is mainly composed of a by-product generated in the beginning of the reaction, might be formed in the surface of paraformaldehyde and plays a key role in controlling the formation of the intermediate by means of restricting the decomposition of paraformaldehyde.

Glycerol and derived solvents: new sustainable reaction media for organic synthesis

“…In particular, many substrates, such as styrenes, primary amines, 2-naphthol, 4-hydroxy-6-methyl-2-pyrone and 4-hydroxy-1-methyl-2-quinolone, could be readily assembled with 1,3-cyclohexadiones and formaldehyde in glycerol, under catalyst-free conditions, to afford the elaborated polycyclic compounds 17-21 in moderate to high yields (Scheme 16). 49 In…”

The Role of Green Solvents and Catalysts at the Future of Drug Design and of Synthesis

“…Beside presented methods, green chemistry is in progress to give diazepine derivatives. Lutfullah et al have published an article in which they have displayed a green reaction using nanocatalyst to obtain tricyclic benzodiazepine derivatives 1,2-diamino benzene (83), dimedone (23), and aromatic aldehydes (84) were reacted in the reaction tube in which nanocatalyst was presented. All reactions were run in microwave synthesizer which is a good tool for green chemistry.…”

Chemical trapping and characterization of small oxoacids of sulfur (SOS) generated in aqueous oxidations of H2S

“…1 ; an analogous thioether adduct is observed using bromobimane and iodoacetamide traps ( S2 ). In the same reaction mixtures, the sulfinyl tautomer is trapped by consecutive Knoevenagel and Michael additions with dimedone, yielding tetravalent S species, ylide 6 [41] , [42] . The SICs of these species, along with [M+H + ] LCMS spectra are shown in Fig.…”