Roberto Ballini

Three-component process for the synthesis of 2-amino-2-chromenes in aqueous media

Abstract The reaction of an aldehyde, malononitrile and a phenol in water at reflux in the presence of cetyltrimethylammonium chloride (CTACl) as catalyst affords a one-pot synthesis of 2-amino-2-chromenes.

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.

Nitroaldol (Henry) reaction catalyzed by amberlyst A-21 as a far superior heterogeneous catalyst

Abstract β-Nitroalcohols can be efficiently obtained with the help of Amberlyst A-21, as heterogeneous basic catalyst, with or without solvent. This method is far superior to the heterogeneous catalysts previously reported for the nitroaldol (Henry) reaction, in fact it gives higher yields with primary and secondary nitroalkanes, the formation of by-products such as nitroalkenes is avoited even if aromatic aldehydes are used, and it is indipendent from the ratio catalyst/starting materials. Moreover its mildness is demonstrated by the no-epoxidation of bromhydrins.

Solvent free synthesis and deprotection of 1,1-diacetates over a commercially available zeolite Y as a reusable catalyst

Abstract Chemoselective synthesis and deprotection of 1,1-diacetates have been performed in good yields and in the absence of any solvent by zeolite HSZ-360 as a new reusable catalyst.

Recent developments on the chemistry of aliphatic nitro compounds under aqueous medium

Aliphatic nitro derivatives represent an important class of useful molecules in organic synthesis. The versatility of these compounds is largely due to their easy availability and transformation into a variety of diverse functionalities. Moreover, aliphatic nitro compounds are very important building blocks (both as nucleophiles or as electrophiles) for the generation of new carbon–carbon bonds, mainly via nitroaldol-Henry reactions, Michael reactions and Diels–Alder cycloadditions. Usually, organic solvents are believed to be necessary for achieving the best efficiency in the reactions of aliphatic nitro compounds and, only recently, it has been shown that these reactions are also very efficient using water as reaction medium. Such progress in the chemistry of aliphatic nitro compounds is particularly attractive to industry since the replacement of toxic solvents still remains a crucial (and expensive) challenge. Thus, this report is focused on the chemistry of aliphatic nitro derivatives performed in aqueous media.

1,3-Dioxolanes from carbonyl compounds over zeolite HSZ-360 as a reusable, heterogeneous catalyst

Abstract Carbonyl compounds are converted, in good yields, into their 1,3-dioxolanes over zeolite HSZ-360, as a new reusable catalyst. Good chemoselectivity is also observed.

The Michael reaction of nitroalkanes with conjugated enones in aqueous media

Abstract The Michael reaction of various nitroalkanes with conjugated enones can be performed in NaOH 0.025 M and in the presence of cetyltrimethylammonium chloride (CTACl) as cationic surfactant, without any organic solvent. Good yields of the products are obtained even with hindered starting materials.

Use of heterogeneous catalyst KG-60-NEt2 in Michael and Henry reactions involving nitroalkanes

The N,N-diethylpropylamine supported on amorphous silica (KG-60-NEt2) catalyses the formation of carboncarbon bonds by nitroalkanes through both the nitroaldol (Henry) and Michael reactions. The catalyst shows general utility with a variety of electrophilic acceptors. Moreover, the catalyst can be reused for two further cycles without loss of the activity.

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.

Amberlyst 15: A Practical, Mild and Selective Catalyst for Methyl Esterification of Carboxylic Acids.1

Abstract Mild and selective methyl esterification of carboxylic acids are realized using Amberlyst 15 as acid catalyst in methanol. No race mization, epimerization or ketalization products have been observed with this method. Excellent results are obtained in the esterifications of bile acids.