Browsing by Author "Mancuso, Raffaella"

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New palladium catalyzed carbonylation processes for the synthesis of molecules of applicative interest
(2016-02-26) Ziccarelli, Ida; Mancuso, Raffaella; Gabriele, Bartolo
In the present investigation we have developed new palladium-catalyzed carbonylation processes for the synthesis of molecules of applicative interest. In particular, isoindolinone and isobenzofuranimine derivatives have been synthetized starting from 2-alkynylbenzamides by a divergent PdI2-catalyzed multicomponent carbonylative approach, depending on the nature of the external nucleophile and reaction conditions. Thus, oxidative carbonylation of 2- ethynylbenzamides, bearing a terminal triple bond, carried out in the presence of a secondary amine as external nucleophile, selectively led to the formation of 3- [(dialkylcarbamoyl)methylene]isoindolin-1-ones. On the other hand, 3-[(alkoxycarbonyl)methylene]-isobenzofuran-1(3H)imines were selectively obtained when the oxidative carbonylation of 2-alkynylbenzamides, bearing a terminal or an internal triple bond, was carried out in the presence of an alcohol R'OH (such as methanol or ethanol) as the external nucleophile and HC(OR')3 as a dehydrating agent, necessary to avoid substrate hydrolysis. Isoindolinone derivatives were used as starting material to obtain the corresponding spiro-isoindolin isoxazolidines, able to work as inhibitors of the p53-MDM2 interaction: biological test showed that these compounds have antiproliferative activity on cancer cell lines of neuroblastoma, colorectal adenocarcinoma and hepatocarcinoma in the μM range. Isobenzofuranimine derivatives, instead, showed a strong phytotoxic effect on shoot and root systems of Arabidopsis thaliana, a weed which compete with crops for edaphic resources such as water and nutrients. Furo-furanone derivatives have been synthetized by PdI2-catalyzed oxidative carbonylation starting from 4-yn-1,3-diols, substrates bearing themselves nucleophilic groups in a suitable position to give a “double” intramolecular nucleophilic attack so as to obtain functionalized bicyclic molecules. Biological assay showed that these compounds are promising anticancer agents. Finally, part of this PhD was spent at Leibniz Institute for Catalysis in Rostock University in order to develop a new heterogeneous catalyst based on palladium via immobilization and pyrolysis on activated carbon. Palladium supported on N-doped carbon was applied to the alkoxycarbonylation of aryl iodides to benzoates, important feedstocks and key intermediates for pharmaceuticals.
Pdl2 catalyzed oxidative carbonylation of anime derivatives leading to macrolactam, urea, oxamide, oxazolidinone and benzoxazolone derivatives
(2014-12-01) Dnyaneshwar, Shriram Raut; Bartolino, Roberto; Bartolo, Gabriele; Mancuso, Raffaella
Sintesi di derivati benzofuranici e chinolinici mediante eterociclizzazione Pd-0 Cu-Catalizzata
(2006) Mancuso, Raffaella; Gabriele, Bartolo; Salerno, Giuseppe; Sindona, Giovanni
Synthesis of high value added molecules by catalytic and heterocyclization approaches
(2018-05-11) Mancuso, Raffaella; Critelli, Salvatore; Gabriele, Bartolo
In the present PhD thesis is reported the development of new sustainable catalytic processes for the production of high value added molecules starting from simple and readily available building blocks, under safer and low-intensive energy conditions, by iodocyclization, carbonylation and cycloisomerization reactions in non-conventionl solvents such as Deep Eutectic Solvents (DES) and Ionic Liquids (ILs). Catalytic processes, in which several different units can be assembled in one step in ordered sequence under the promoting action of a suitable catalyst, are destined to play a central role in current synthesis. Of particular importance is the development of novel catalytic processes for the reconversion of CO and CO2 into organic molecules. CO is an inexpensive and readily available C-1 source, and its incorporation into an organic substrate (carbonylation) is now widely recognized as a very important tool in synthesis. Nowadays, carbonylations are at the basis of important industrial technologies for the conversion of easily available feedstocks into useful products of our daily life, and find increasing application in organic synthesis for the production of fine chemicals. CO2 is another very attractive C-1 feedstock for organic synthesis. It is ubiquitously available, low toxic, and abundant. Since the industrial revolution, CO2 has been continuously released in huge amounts in the atmosphere from all combustion processes of organic carbon for the production of energy. Therefore, the efficient reconversion of CO2 (“spent” carbon) into high value added products (“working”-carbon; chemicals, fuels, materials) is one of the current most important strategic goals in chemical research, which will allow to make a step forward toward a more sustainable economy. Non-conventional solvents, such as polyethylene glycols, ionic liquids (ILs), Deep Eutectic Solvents, or supercritical CO2 are less toxic and more eco-friendly than traditional organic solvents. Their use in the processes studied in this thesis allowed an easier separation and purification of the products and, in the case of catalytic reactions, the recycling of the catalyst as well. The direct syntheses of ureas, oxamides, 2-oxazolidinones, and benzoxazolones by oxidative carbonylation of amines, β-amino alcohols, and 2-aminophenols allows obtaining high value added molecules, with a large number of important applications in several fields, starting from very simple building blocks. In chapter two is reported the possibility to carry out these transformations using the PdI2/KI catalytic system in an ionic liquid (IL), such as BmimBF4, as the solvent. The catalyst-solvent system can be recycled several times with only a slight loss of activity, while the product can be easily recovered by crystallization. In the some chapter the reactivity of 2-(2-alkynylphenoxy)anilines under PdI2/KI-catalyzed oxidative carbonylation conditions has been studied. 8-endo-dig cyclization preferentially occurred when the triple bond was terminal, leading to the formation of carbonylated β-lactam derivatives. These novel medium-sized heterocyclic compounds showed anti-tumor activity against both estrogen receptor-positive (MCF-7) and triple negative (MDA-MB-231) breast cancer cell lines. In chapter three is showed that the heterocyclodehydration and iodocyclization of readily available 1-mercapto-3-yn-2-ols has been performed in a deep eutectic solvent (DES), that is, ChCl/Gly, as a non-conventional green solvent. The DES/catalytic system could be easily recycled several times without appreciable loss of activity, after extraction of the thiophene product with hexane or Et2O. In chapter three the first example of a tandem thionation/S-cyclization process leading to benzo[c]thiophene-1(3H)-thione and 1H-isothiochromene-1-thione derivatives, starting from 2-alkynylbenzoic acids, is also reported. Depending on the nature of the substituent at the distal β carbon of the triple bond, either benzothiophenethiones or isothiochromenethiones were obtained selectively, in high to excellent yields. In chapter four a novel methodology to easily access imidazolidin-2-ones from propargylamines, primary amine and CO2 with guanidine bases as catalysts under solvent-free conditions is reported. Bicyclic guanidines, able to catalyze the formation of oxazolidinones from propargylamines and CO2, are presented for the first time as effective organocatalysts for the chemical fixation of CO2 into linear and cyclic ureas.
Towards more sustainable organic processes : heterocyclizations in non-conventional solvents
(2017-09-19) Maner, Asif S.; Carbone, Vincenzo; Gabriele, Bartolo; Mancuso, Raffaella
This thesis reports the synthesis of important heterocyclic derivatives by iodocyclization, carbonylation and cycloisomerization reactions in Non-Conventionl solvents like deep eutectic solvents (DES) and Ionic Liquids (ILs). In chapter one general aspects of green and sustainable chemistry and introduction to eco-friendly green solvents such as water, DES, ScCO2 and ILs are described. Carbonylation processes, their advantages, types were described along with the application of transition metal catalysis in the carbonylation reactions with mechanistic approaches discussed. In chapter two, we describe a convenient and general method for the synthesis of substituted thiophenes through heterocyclodehydration and iodocyclization of readily available 1-mercapto-3-alkyn-2-ols in DES as the solvents. In chapter three we discuss a convenient carbonylative approach to 2-oxazolidinone derivatives carried out in an ionic liquid as the solvent (EmimEtSO4) is presented. It is based on the sequential concatenation of two catalytic cycles, both catalyzed by the same metal species (auto-tandem catalysis). In chapter four we present iodocyclization reactions to obtain iodinated isobenzofuranones and isochromenones by iodolactonization of 2-alkynyl benzoic acids in ionic liquids. In particular here we have developed divergent syntheses of (E)-3-(iodoalkylidene) isobenzofuran-1(3H)-ones and 4-iodo-1H-isochromen-1-ones by base-free Iodolactonization of 2-alkynylbenzoic acids in ionic liquids. In chapter five we report the cycloisomerization of readily available 2-alkynylbenzoic acids using an ionic liquid as the reaction medium in the presence of CuCl2 as a simple and inexpensive catalyst. Although in principle two different cyclization pathways can be followed, leading to either 5-exo-dig mode or 6-endo-dig mode, we have found that substrates bearing an aryl group on the triple bond or a terminal triple bond can be selectively converted into the isobenzofuranone derivatives, using N-ethyl-N-methylmorpholinium dicyanamide (Mor1,2N(CN)2) as the solvent. On the other hand, and in a complementary manner, substrates substituted with an alkyl or an alkenyl group on the triple bond selectively led to isochromenones when the reaction was carried out EmimEtSO4 and with excellent recyclability of the catalyst/ionic liquid system.