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Efficient Lewis Acid Systems for the A3 Coupling reaction
No full textEfficient Lewis Acid Systems for the A3 Coupling reaction
Cimarelli C., a Navazio F.,a Rossi F. V.a, Del Bello F., Marcantoni E.a
aSchool of Science and Technology, Chemistry Division, University of Camerino, Via S. Agostino 1, 62032 Camerino; e-mail: [email protected]
Propargylamines are an attractive class of molecules because of their particular molecular skeleton, that contains an amine group located in β-position to an alkyne moiety suitable for many chemical transformations. In recent years they received a growing interest as key intermediates for several biologically active compound, natural products and also different heterocycles.[1,2]
Our goal was the development of green and simple methodologies for the synthesis of secondary propargylamines by Lewis acid catalyzed or promoted A3 reaction among aldehydes, alkynes and primary amines, that are in general less applied in such reactions because of their lower reactivity. In particular, we studied two different pathway: the CuSO4/NaI system in one pot fashion and the CeCl3/CuI system in one pot/two steps way (Scheme 1).
Scheme 1. CeCl3·7H2O/CuI and CuSO4/NaI catalyzed A3 reaction.
Heptahydrated CeCl3 is reported to be an excellent catalyst for many useful organic transformation as the synthesis of imines. Its efficacy as Lewis acid is enhanced in the presence of inorganic iodides/iodide salt and being cooper the transition metal of choice for A3 reactions, CuI was used.[3]
Also the CuSO4/NaI couple has revealed to be an interesting Lewis acid system as an alternative to CeCl3/CuI system which allow the formation of CuI in situ by quantitative spontaneous reaction that takes place in few seconds.[4]
Typically CuSO4/NaI catalysed reactions are faster than CeCl3·7H2O/CuI reactions, but suffer of some disadvantages, such as lower yields, and a narrower applicability. Both reaction conditions have been applied to different aldehydes (aromatic and aliphatic) and to chiral starting materials, the amine in general has no effect on the reaction outcome.
The relevant Glaser coupling drawback observed in the CuSO4/NaI system conditions has been suppressed by adding some benzoic acid, and has not been observed with the CeCl3/CuI system.
References:
1) Lauder, K.; Toscani, A.; Scalacci, N.; Castagnolo, D. Chem. Rev. 2017, 117, 14091.
2) Peshkov, V. A.; Pereshivko, O. P.; Van der Eycken, E. V. Chem. Soc. Rev. 2012, 41, 3790.
3) G. Bartoli, E. Marcantoni, M. Marcolini, L. Sambri, Chem. Rev. 2010, 110, 6104.
4) Bailey, A. D.; Cherney, S. M.; Anzalone, P. W.; Anderson, E. D.; Ernat, J. J.; Mohan, R. S. Synlett 2006, 215
The CeCl3 Lewis Acid Promoter in the Stereoselective Construction of Carbon-Carbon Double Bonds
No full textThe presence of a C-C double bond in polyfunctionalized organic molecules is a crucial requirement
for the control of its biologically activity.(1) The importance of having a site in the molecule that is
able to generate geometrical isomerization of a carbon-carbon double bond stimulated the
development of new olefination methodologies. In particular, some efforts focused on the ability of
Lewis acids to provide a cheap alternative for the synthesis of molecules with C-C double bond in a
highly stereoselective fashion.
For several years, we have been investigating CeCl3 promoted organic reactions. This Lewis acid has
been found to efficiently promote carbon-carbon (2) and carbon-heteroatom bond formation
reactions.(3) In addition to being green in nature (4), CeCl3 has been widely used for both inter- and
intramolecular reactions for the synthesis of organic molecules with significant biological
importance.
Regarding the total synthesis of biologically active small molecules containing a carbon-carbon
double bond, we saw the possibility to employ CeCl3 in the stereoselective construction of 2,3-
dihydropyridones 1,(5) and 1,2-dihydroquinolines 2.(6)
The additional advantage of using CeCl3 in a reaction includes its selectivity and tolerance in the
presence of other functional groups. For instance, it can be used during the functionalization of
molecules at late stage involving complex molecules or undesirable use of protecting groups.
Introduction of C-C double bonds, which are known to increase the activity in macrolides against
bacterial RNA polymerase, is currently in progress in our laboratory.
References: 1. Shen, X.; Nguyen, T. T.; Koh, M. J.; Xu, D.; Speed, A. W.; Schrock, R. R.; Hoveyda, A. H. Nature 2017,
541, 380-385. 2. Bartoli, G.; Marcolin, M.; Sambri, L.; Marcantoni, E. Chem. Rev. 2010, 110, 6104-6143. 3. Properzi, R.
Marcantoni, E. Chem. Soc. Rev. 2014, 43, 779-791. 4. Cimarelli, C.; Di Nicola, M.; Diomedi, S.; Giovannini, R.;
Hanprecht, D.; Properzi, R.; Sorana, F.; Marcantoni, E. Org. Biomol. Chem. 2015, 13, 11687-11695. 5. Bordi, S.;
Cimarelli, C.; Lupidi, G.; Marsili, L.; Piermattei, P.; Marcantoni, E. J. Org. Chem. 2017, in preparation. 6. Cimarelli, C.;
Bordi, S.; Piermattei, P.; Pellei, M.; Del Bello, F.; Marcantoni, E. Tetrahedron 2017, submitted
The A3 Coupling Reactions Catalyzed by Efficient Lewis Acid Systems
No full textPropargylamines belong to a widely studied1 class of building blocks because of their
particular molecular skeleton that contains an amine group, suitable for nucleophilic reactions, located
in E-position to an alkyne moiety, that can act both as an electrophile and as a source of electrons in
nucleophilic reactions.2
Our goal was the development of green and simple Lewis acid catalyzed methodologies to
the A3 reaction for the synthesis of primary propargylamines from aldehydes, primary amines and
alkynes. In particular, we applied two different Lewis acid catalysts to this reaction: the CuSO4/NaI
system in one pot fashion and the CeCl3/CuI system in one pot/two steps way.
Figure 1 – CeCl3·7H2O/CuI and CuSO4/NaI catalyzed A3 reaction. Reaction conditions:
i) MgSO4, CeCl3·7H2O 30% mol, solventless, N2, r.t., 0.25h.
ii) CuI 30% mol, solventless, N2, 40°C
iii) CuSO4 30% mol/NaI 60% mol, PhCOOH 5% mol, solventless, N2, 80°C
Heptahydrated CeCl3 is a very good catalyst for the formation of imines, widely used also in
the synthesis of several classes of organic compounds.3 Its efficacy is enhanced in the presence of
inorganic iodides4 and being copper the transition metal of choice for A3 reactions, CuI was used.
Also the CuSO4/NaI couple has revealed to be an interesting Lewis acid system, alternative
to CeCl3/CuI system. The reaction has been applied also to chiral starting materials and, in general,
the amine has no effect on the reaction outcome. Typically CuSO4/NaI catalysed reactions are faster,
but suffer of some disadvantages, such as lower yields, and a narrower applicability. The relevant
Glaser coupling drawback observed in these conditions has been suppressed by adding some benzoic
acid, and has not been observed with the CeCl3/CuI system.
References:
[1] K. Lauder, A. Toscani, N. Scalacci, D. Castagnolo Chem. Rev. 2017, 117, 14091 – 1420.
[2] V. A. Peshkov, O. P. Pereshivko, E. V. Van der Eycken Chem. Soc. Rev. 2012, 41, 3790 – 3807.
[3] R. Properzi, E. Marcantoni Chem. Soc. Rev., 2014, 43, 779 - 791.
[4] G. Bartoli, E. Marcantoni, M. Marcolini, L. Sambri Chem. Rev. 2010, 110, 6104 – 6143
Simulación numérica de flujos supersónicos e hipersónicos
No full textFil: Gutiérrez Marcantoni, Luis F. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Aeronáutica; Argentina.Fil: Gutiérrez Marcantoni, Luis F. Universidad Nacional de Córdoba. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Tamagno, José P. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Aeronáutica; Argentina.Fil: Elaskar, Sergio A. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Aeronáutica; Argentina.Fil: Elaskar, Sergio A. Universidad Nacional de Córdoba. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.En este trabajo varias simulaciones de flujos supersónicos (M > 1) e hipersónicos (M 1),
son construidas utilizando el ejecutable rhoCentralFoam del paquete de herramientas de libre
distribución que provee openfoamTM [1, 2]. En flujos supersónicos e hipersónicos se requieren esquemas numéricos que permitan capturar discontinuidades (p. ej. ondas de choque, superficies
de contacto), con precisión y sin oscilaciones espurias. En métodos caracterizados por su efectividad en capturar estas discontinuidades, la generación de los correspondientes flujos numéricos
generalmente involucra el uso de solvers de Riemann (1989). Estos solver s, si bien efectivos, son
de por si complejos y difíciles de implementar en una malla con celdas poliédricas y arbitrario
número de caras (Ncaras > 3). Una técnica alternativa que no utiliza solvers de Riemann y que
también provee soluciones con adecuada exactitud y sin oscilaciones utilizando esquemas centrales, ha sido propuesta por Kurganov et al. [3, 4]. Esta técnica alternativa ha sido implementada en
openfoamTM y es utilizada con rhoCentralFoam. Las simulaciones a presentar incluyen los flujos
externos sobre cuerpos romos (bidimensionales y axial simétricos) y la combinación flujo externointerno propia de una toma de aire supersónica. Los resultados obtenidos con estas simulaciones
se comparan con los analíticos, numéricos o experimentales producidos por otras fuentes.Fil: Gutiérrez Marcantoni, Luis F. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Aeronáutica; Argentina.Fil: Gutiérrez Marcantoni, Luis F. Universidad Nacional de Córdoba. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Tamagno, José P. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Aeronáutica; Argentina.Fil: Elaskar, Sergio A. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Aeronáutica; Argentina.Fil: Elaskar, Sergio A. Universidad Nacional de Córdoba. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Ingeniería Aeroespacia
Security-Oriented Formal Techniques
No full textSecurity of software systems is a critical issue in a world where Information Technology is becoming more and more pervasive. The number of services for everyday life that are provided via electronic networks is rapidly increasing, as witnessed by the longer and longer list of words with the prefix "e", such as e-banking, e-commerce, e-government, where the "e" substantiates their electronic nature. These kinds of services usually require the exchange of sensible data and the sharing of computational resources, thus needing strong security requirements because of the relevance of the exchanged information and the very distributed and untrusted environment, the Internet, in which they operate. It is important, for example, to ensure the authenticity and the secrecy of the exchanged messages, to establish the identity of the involved entities, and to have guarantees that the different system components correctly interact, without violating the required global properties
Qubit entanglement generation by Gaussian non-Markovian dynamics
No full textWe consider two qubits interacting with a common bosonic bath, but not directly between themselves.
We derive the (bipartite) entanglement generation conditions for Gaussian non-Markovian dynamical maps and show that they are similar as in the Markovian regime; however, they depend on different physical coefficients and hold on different time scales. Indeed, for small times, in the non-Markovian regime entanglement is possibly generated on a shorter time scale (/ t2) than in the
Markovian one (/ t). Moreover, although the singular coupling limit of non-Markovian dynamics yields Markovian ones, we show that the same limit does not lead from non-Markovian entanglement generation conditions to Markovian ones. Also, the entanglement generation conditions do not depend on the initial time for non-Markovian open dynamics resulting from couplings to bosonic
Gaussian baths, while they may depend on time for open dynamics originated by couplings to classical, stochastic Gaussian environments
Qubit entanglement generation by Gaussian non-Markovian dynamics
No full textWe consider two qubits interacting with a common bosonic bath, but not directly between themselves. We derive the (bipartite) entanglement generation conditions for Gaussian non-Markovian dynamical maps and show that they are similar as in the Markovian regime. However, they depend on different physical coefficients and hold on different time scales. Indeed, for small times, in the non-Markovian regime entanglement is possibly generated on a shorter time scale (α t2 ) than in the Markovian regime (α t). Moreover, although the singular coupling limit of non-Markovian dynamics yields Markovian ones, we show that the same limit does not lead from non-Markovian entanglement generation conditions to Markovian ones. Also, entanglement generation conditions do not depend on the initial time for non-Markovian open dynamics resulting from couplings to bosonic Gaussian baths, while they may depend on time for open dynamics originated by couplings to classical, stochastic Gaussian environments
Art. 12
No full textCommentario all'art. 12 della Dichiarazione universale dei diritti dell'uomo del 1948 (rispetto della vita privata
Simulación de flujos compresibles con openFoam™
No full textMaestría en Ciencias De La Ingeniería - Mención AeroespacialFil: Gutiérrez Marcantoni, Luis F. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina.Fil: Gutiérrez Marcantoni, Luis F. Fuerza Aérea Argentina. Universidad de la Defensa Nacional. Centro Regional Universitario Córdoba IUA; Argentina.En esta tesis se describen los resultados obtenidos con las simulaciones numéricas de dos
tipos de problemas en los cuales el fluido debe necesariamente ser considerado compresible. En uno, se simula un caso de combustión difusiva turbulenta a baja velocidad y en
otro, la simulación se aplica a casos típicos de aerodinámica supersónica. Ambas simulaciones fueron desarrolladas aplicando las herramientas de libre distribución que provee
openfoam™. Con la combustión se utilizan ecuaciones de conservación inestacionarias para la masa, los momentos, la energía y la conservación de las especies, promediadas según
Favre y para la turbulencia se emplea un modelo k −ε modificado. Para resolver las ecuaciones de conservación discretizadas, se emplea el método PISO (Pressure Implicit with
Splitting of Operators), que conlleva a la derivación de una ecuación independiente para
la presión. La cinética química es modelada mediante una única reacción global y para
tener en cuenta la interacción química-turbulencia se implementa el concepto del reactor
parcialmente mezclado. El cálculo de los términos fuentes presentes en las ecuaciones de
conservación de las especies químicas, requiere la integración de ecuaciones diferenciales
ordinarias stiffs. openFoam proporciona un esquema numérico que garantiza estabilidad
en el cómputo de estos términos. La simulación numérica del benchmark conocido como
llama D, se compara con datos experimentales obtenidos por Sandia National Laboratories.
Las simulaciones numéricas de los flujos supersónicos son desarrolladas empleando los ejecutables sonicFoam y rhoCentralFoam. Las principales diferencias entre estos ejecutables
son: sonicFoam usa la presión como variable dependiente y en consecuencia utiliza el método PISO como técnica resolutiva; rhoCentralFoam mantiene la densidad como variable
dependiente y en lugar de usar solvers de Riemann como técnica resolutiva, emplea los
esquemas alternativos de Kurganov et al. . En esta tesis se evalúan las ventajas y desventajas derivadas de la aplicación en simulaciones supersónicas, de los dos ejecutables
citados. Con tal propósito, los siguientes flujos supersónicos fueron considerados: la cuña
(o rampa), perfil tipo doble cuña y el cuerpo romo (bidimensional y axisimétrico). Estos
flujos tienen solución analítica o cuentan con datos experimentales con que comparar los
resultados de las simulaciones numéricas. En todos los casos se supone que el fluido (aire)
se comporta como un gas no viscoso y calórico perfecto.This thesis describes results obtained from numerical simulations of two types of problems
in which the fluid flow must necessarily be considered compressible. In one type, a low
speed diffusive combustion problem is simulated and in the other one, the simulation is
applied to typical supersonic aerodynamics problems. Both simulations were developed
by employing free distribution tools provided by openFoam.
Favre averaged unsteady mass, momentum, energy and species conservation equations
are used in the combustion problem and to account for turbulence, a modified k-e model
is used. The conservation equations are solved utilizing a pressure implicit with splitting
of operators (PISO) algorithm, which requires the addition of an extra equation for the
pressure. The chemical kinetics is modeled by only one step global reaction and the
partially stirred reactor concept (PaSR) is implemented to consider chemistry-turbulence
interactions. To compute source terms in the species conservation equations, sets of
stiff ordinary differential equations (ODEs) have to be solved. openFoam provides a
numerical scheme that ensure well enough stability in computing these terms. A numerical
simulation of the Sandia flame “D” is compared with experimental data available from
Sandia National Laboratories (USA).
Supersonic flow numerical simulations, are performed with sonicFoam and rhoCentralFoam solvers. The main difference between them arise from the fact that sonicFoam
uses the pressure as dependent variable and, consequently, the PISO algorithm, whereas
rhoCentralFoam keeps density as a dependent variable and, therefore, can use the central schemes introduced by Kurganov et al. as resolvent technique. In this thesis, the
advantages and disadvantages of the cited solvers to handle supersonic flow simulations
are evaluated by applying them to three cases: flow over a wedge, a double wedge airfoil
and over two dimensional and axial symmetrical blunt bodies. These flow cases have analytical solutions or available experimental data to compare with numerical simulations
results. In all cases the flow (air) is assumed to behave as a inviscid and caloric perfect
gas.Fil: Gutiérrez Marcantoni, Luis F. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina.Fil: Gutiérrez Marcantoni, Luis F. Fuerza Aérea Argentina. Universidad de la Defensa Nacional. Centro Regional Universitario Córdoba IUA; Argentina
How to Turn Poultry Manure into Valuable Resources: A Circular Business Model for Resilient and Sustainable Small and Medium-Sized Farms
No full textThis paper illustrates how small and medium-sized farmers can resolve the complex issue of poultry manure disposal by implementing an innovative technology with the aims of reducing emissions and waste and transforming manure into precious resources for the production of energy and fertilizers. After a literature review, a case study is analyzed to identify the main elements of a circular business model that can realize a strategic priority, such as defining production and consumption processes compatible with sustainability, circularity, and resilience. This paper identifies the main elements that constitute the “value proposition,” “value creation and delivery,” and “value captured,” showing the potential benefits in terms of competitiveness and profitability. This good practice may be replicated by other breeding and agricultural companies that want to be sustainable and resilient. The analyzed topic is a key concern given the great quantity of energy and chemical substances used by farms and the challenges posed by current dramatic events, such as the Russia–Ukraine conflict and the COVID-19 pandemic, which have led to less availability of energy and fertilizers and unsustainable prices
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