Silvia Carloni

A revision of the Biginelli reaction under solid acid catalysis. Solvent-free synthesis of dihydropyrimidines over montmorillonite KSF

Abstract The reaction of aldehydes, β-dicarbonyl compounds and urea (Biginelli reaction) has been performed over solid acid catalysis, under solventless conditions or in water affording dihydropyrimidines in good yield and selectivity. Dihydropyrimidines4 were obtained in good yield and selectivity by reacting aldehydes, β-dicarbonyl compounds and ureas in the presence of montmorillonite KSF under solventless conditions. Download : Download full-size image

Zeolite HSZ-360 as a new reusable catalyst for the direct acetylation of alcohols and phenols under solventless conditions

Abstract Alcohols and phenols were efficiently acylated with acetic anhydride without solvent over zeolite HSZ-360. The catalyst can be reused with no activity loss.

Clean synthesis in water. Part 2: Uncatalysed condensation reaction of Meldrum's acid and aldehydes

Abstract The environment-friendly condensation of Meldrums acid and aromatic, heteroaromatic and hindered aliphatic aldehydes is performed carrying out the reaction in water at 75°C for 2 h, avoiding the addition of any catalyst.

Solvent free tetrahydropyranylation of phenols and alcohols over zeolites HSZ as reusable catalysts

Abstract Phenols and alcohols are tetrahydropyranylated in the presence of zeolites HSZ in good to excellent yields and selectivities. Addition of methanol performs the complete deprotection.

Uncatalysed reactions in water: Part 2. Preparation of 3-carboxycoumarins

A simple, efficient and environmentally friendly procedure has been developed for the reaction of Meldrum’s acid with salicylaldehydes. 3-Carboxycoumarins 5 were synthesised in high yields (78–96%) and excellent selectivities (95–98%) by carrying out the reaction in water at reflux for 10 h, avoiding the addition of any catalyst.

Homogeneous versus heterogeneous approach to the catalytic desymmetrisation of meso-anhydrides promoted by cinchona alkaloids

Abstract The ring opening of the cyclic prochiral cis-1,2,3,6-tetrahydrophthalic anhydride 1 with methanol was investigated by using cinchona alkaloids such as quinine (QN) and quinidine (QD) as base catalysts. The effect of solvent, temperature, reaction time and catalyst amount on the yield and enantioselectivity was examined in the model reaction under homogeneous conditions. The best results (yields and ee values) were achieved by using QD as chiral catalyst. Moreover, as a hypothetical intermediate, an adduct between the anhydride and the catalyst which is responsible for both reagents activation and stereocontrol is proposed. QD was then supported to both amorphous (KG-60) and mesoporous (MCM-41) siliceous materials through a thioether linker giving catalysts called KG-60-QD and MCM-41-QD, respectively. These materials were characterised by determining surface area, loading value and thermal stability. Comparison experiments showed that supported catalysts afforded product 3 in slightly lower yields and ee values with respect to the homogeneous counterpart.

Allylic oxidation of olefins in the presence of Cu-Na-HSZ-320 zeolite as reusable solid catalyst

Abstract The Cu-Na-HSZ-320 zeolite can be utilised as an efficient and reusable catalyst in the allylic oxidation of olefins with tert -butyl perbenzoate to give the corresponding allylic esters in good yield and excellent selectivity.