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Procopio A.,University della Magna Graecia Complesso Nini Barbieri | Cravotto G.,University of Turin | Oliverio M.,University della Magna Graecia Complesso Nini Barbieri | Costanzo P.,University della Magna Graecia Complesso Nini Barbieri | And 2 more authors.
Green Chemistry | Year: 2011

A new simple and effective method for the formation/cleavage of O-tert-butoxy carbonates of alcohols and phenols is proposed. Mesoporous silica-supported Er(iii) (ErIII-MCM-41) was used as an efficient and reusable solid catalyst in the solvent-free ultrasound-assisted synthesis of Boc-carbonate derivatives of a wide range of alcohols and phenols. The fast, selective deprotection of Boc-derivatives is achieved with a very low amount of Er(OTf)3 in ethanol under microwave irradiation. Therefore, the entire protection/de-protection process is very attractive, from the point of view of sustainability. © 2011 The Royal Society of Chemistry.


Rosati O.,University of Perugia | Curini M.,University of Perugia | Marcotullio M.C.,University of Perugia | Oball-Mond G.,University of Perugia | And 2 more authors.
Synthesis | Year: 2010

The reaction of various coumarins with cyanoacetamide derivatives under basic conditions (sodium ethoxide, piperidine or 2,2,6,6-tetramethylpiperidine), proceeds via an interesting process which involves skeletal rearrangement of the coumarin, a Michael addition and two cyclizations to afford 5-amino-1,10b-dihydro-2H-chromeno[3,4-c]pyridine-2,4(3H)-diones. The same reaction in the presence of N,N¢-ethane-1,2-diylbis(2-cyanoacetamide) gives the corresponding mono and bis 5-amino-1,10b-dihydro-2H-chromeno[3,4-c] pyridine-2,4(3H)-diones. © Georg Thieme Verlag Stuttgart.


Procopio A.,University della Magna Graecia Complesso Nini Barbieri | Costanzo P.,University della Magna Graecia Complesso Nini Barbieri | Curini M.,University of Perugia | Nardi M.,University of Calabria | And 2 more authors.
Synthesis | Year: 2011

An eco-compatible method, which permits the formation or cleavage of tert-butyl ethers of alcohols and phenols, is proposed. The protection step is performed in solvent-free conditions at room temperature using catalytic amount of Er(OTf)3. The catalyst is easily- recovered from the aqueous phase and reused several times without significant loss of activity. The deprotection step developed is also highly eco-friendly since the tert-butyl group is removed very quickly from alcohols and phenols in methanol using MW irradiation-. © Georg Thieme Verlag Stuttgart · New York.


Pasqua L.,University of Calabria | Procopio A.,University della Magna Graecia Complesso Nini Barbieri | Oliverio M.,University della Magna Graecia Complesso Nini Barbieri | Paonessa R.,University della Magna Graecia Complesso Nini Barbieri | And 5 more authors.
Journal of Porous Materials | Year: 2013

Hybrid materials obtained through a Microwave-assisted grafting of organic functional groups on mesoporous silica (MCM-41 type) have been characterized by X-ray powder diffraction, TG-DSC, N2 adsorption, solid state 13C- and 29Si-NMR, TEM and SEM. The studied grafting procedure is effective in the preparation of hybrid organosilicas under solvent-free conditions. Microwaves allows an ultra-fast and clean functionalization of the mesoporous materials and the method has been applied to produce a wide series of functional materials. The hybrid materials maintain the original mesoporous structure when the loading of linked organic groups does not exceed 10 %. In this cases, the slight pore volume reduction is linearly correlated to the organic amount in the product. If functional groups able to interact among them through hydrogen bond are used, hybrid materials exhibit high Organic/SiO2 ratios and low pore volumes due to the formation of a network occluding the pores, where functional groups of free organosilane molecules interacts with the functional groups of molecules linked to the matrix. NMR data confirm that the network is composed by organosilane molecules linked or not to the framework. Acid washing is able to labilize hydrogen bond and open the network. In the case of bulky but chemically inert functionalising agents the network is not produced. © 2012 Springer Science+Business Media New York.

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