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40 results on '"Renzetti, Andrea"'

1. Theory coherent shrinkage of Time-Varying Parameters in VARs

Author

Renzetti, Andrea

Subjects
Economics - Econometrics
Abstract

Time-Varying Parameters Vector Autoregressive (TVP-VAR) models are frequently used in economics to capture evolving relationships among the macroeconomic variables. However, TVP-VARs have the tendency of overfitting the data, resulting in inaccurate forecasts and imprecise estimates of typical objects of interests such as the impulse response functions. This paper introduces a Theory Coherent Time-Varying Parameters Vector Autoregressive Model (TC-TVP-VAR), which leverages on an arbitrary theoretical framework derived by an underlying economic theory to form a prior for the time varying parameters. This "theory coherent" shrinkage prior significantly improves inference precision and forecast accuracy over the standard TVP-VAR. Furthermore, the TC-TVP-VAR can be used to perform indirect posterior inference on the deep parameters of the underlying economic theory. The paper reveals that using the classical 3-equation New Keynesian block to form a prior for the TVP- VAR substantially enhances forecast accuracy of output growth and of the inflation rate in a standard model of monetary policy. Additionally, the paper shows that the TC-TVP-VAR can be used to address the inferential challenges during the Zero Lower Bound period., Comment: 48 pages, 8 figures

Published
2023

2. Modelling and Forecasting Macroeconomic Risk with Time Varying Skewness Stochastic Volatility Models

Author

Renzetti, Andrea

Subjects
Economics - Econometrics
Abstract

Monitoring downside risk and upside risk to the key macroeconomic indicators is critical for effective policymaking aimed at maintaining economic stability. In this paper I propose a parametric framework for modelling and forecasting macroeconomic risk based on stochastic volatility models with Skew-Normal and Skew-t shocks featuring time varying skewness. Exploiting a mixture stochastic representation of the Skew-Normal and Skew-t random variables, in the paper I develop efficient posterior simulation samplers for Bayesian estimation of both univariate and VAR models of this type. In an application, I use the models to predict downside risk to GDP growth in the US and I show that these models represent a competitive alternative to semi-parametric approaches such as quantile regression. Finally, estimating a medium scale VAR on US data I show that time varying skewness is a relevant feature of macroeconomic and financial shocks., Comment: 41 pages,7 figures

Published
2023

5. Labour at Risk

Author

Botelho, Vasco, primary, Foroni, Claudia, additional, and Renzetti, Andrea, additional

Published
2023
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12. Ti[Cl.sub.4]/[Et.sub.3]N-promoted three-component condensation between aromatic heterocycles, aldehydes, and active methylene compounds

Author

Renzetti, Andrea, Dardennes, Emmanuel, Fontana, Antonella, De Maria, Paolo, Sapi, Janos, and Gerard, Stephane

Subjects
Titanium -- Chemical properties, Titanium -- Structure, Chlorine compounds -- Chemical properties, Chlorine compounds -- Structure, Carbonyl compounds -- Chemical properties, Carbonyl compounds -- Structure, Methylene compounds -- Chemical properties, Methylene compounds -- Structure, Biological sciences, Chemistry
Abstract

A method is described to perform one-pot synthesis of polyfunctionalized indole derivatives by a Ti[Cl.sub.4]/[Et.sub.3]N-promoted trimolecular condensation of aldehydes, indole heterocycles, and various activated carbonyl compounds. The method could be extended to the asymmetric Friedel-Crafts reaction of heterocyclic systems.

Published
2008

14. Biological and Mechanistic Characterization of Novel Prodrugs of Green Tea Polyphenol Epigallocatechin Gallate Analogs in Human Leiomyoma Cell Lines

Author

Ahmed, Reda Saber Ibrahim, primary, Liu, Gang, additional, Renzetti, Andrea, additional, Farshi, Pershang, additional, Yang, Huanjie, additional, Soave, Claire, additional, Saed, Ghassan, additional, El‐Ghoneimy, Ashraf Ahmed, additional, El‐Banna, Hossny Awad, additional, Foldes, Robert, additional, Chan, Tak‐Hang, additional, and Dou, Q. Ping, additional

Published
2016
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24. Diastereomer Interconversion via.

Author

Renzetti, Andrea, Di Crescenzo, Antonello, Nie, Feilin, Bond, Andrew D., Gérard, Stéphane, Sapi, Janos, Fontana, Antonella, and Villani, Claudio

Subjects
*CRYSTALLIZATION, *HIGH performance liquid chromatography, *DIASTEREOISOMERS, *THERMODYNAMICS research, *CHIRALITY
Abstract

The three-component reaction of indole, isobutyraldehyde, and methyl acetoacetate affords methyl 2-(acetyl)-3-(1 H-indol-3-yl)-4-methylpentanoate as a single diastereomer. To investigate the origin of the observed diastereoselectivity, the thermodynamics and kinetics of interconversion of diastereomers 1 and 2 in solution were studied by a combination of 1H (NMR) spectroscopy, high-performance (HPLC), , and experiments. The results indicate that interconversion is both acid- and base-catalyzed, and that the alpha carbon is the only stereolabile center in the molecule. The evidence points to an mechanism for the interconversion process. The selective precipitation of 1 in the presence of the equilibrium 1⇆ 2 eventually results in the exclusive formation of 1 (crystallization-induced asymmetric transformation). Chirality 27:779-783, 2015. © 2015 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Published
2015
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30. TiCl4-promoted condensation of methyl acetoacetate, isobutyraldehyde, and indole: a theoretical and experimental study.

Author

Renzetti, Andrea, Marrone, Alessandro, Gérard, Stéphane, Sapi, Janos, Nakazawa, Hiroshi, Re, Nazzareno, and Fontana, Antonella

Abstract

The mechanism of the TiCl4-promoted condensation of methyl acetoacetate, isobutyraldehyde, and indole was studied by a combination of theoretical and experimental techniques. The energy profile of plausible reaction paths was evaluated by DFT calculations, and various reaction intermediates were isolated or observed in solution by NMR spectroscopy. Theoretical and experimental results indicate that the reaction proceeds in three steps, all promoted by titanium: (1) formation of the enolate ion of methyl acetoacetate, (2) Knoevenagel condensation of the enolate ion and aldehyde, and (3) Michael addition of indole to the Knoevenagel adduct. The study sheds light on the role of titanium in the reaction, providing a mechanistic model for analogous reactions. [ABSTRACT FROM AUTHOR]

Published
2015
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33. TiCI4/Et3N-Promoted Three-Component Condensation between Aromatic Heterocycles, Aldehydes, and Active Methylene Compounds.

Author

Renzetti, Andrea, Dardennes, Emmanuel, Fontana, Antonella, De Maria, Paolo, Sapi, Janos, and Gérard, Stéphane

Subjects
*HETEROCYCLIC compounds, *CARBENES, *CONDENSATION, *AROMATIC compounds, *INDOLE
Abstract

A one-pot methodology for the synthesis of polyfunctionalized indole derivatives by a TiCl4/Et3N-promoted trimolecular condensation of aldehydes, indole heterocycles, and various activated carbonyl compounds is reported. Rationalization of these reactions and extension to other heterocyclic systems is also described. [ABSTRACT FROM AUTHOR]

Published
2008
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35. Synthesis of Phthalides and α,β-butenolides by Transition Metal-Catalyzed Activation of C—H Bonds.

Author

Renzetti, Andrea, Fukumoto, Kozo, Silva, Artur M. S., and Marques, Maria Manuel

Subjects
*PHTHALIDES, *HETEROCYCLIC compounds, *HYDROGEN bonding, *MOLECULES, *BUTENOLIDES
Abstract

Phthalides and α,β-butenolides are two related classes of oxygenated heterocycles with a wide range of biological activities. An innovative strategy to prepare these compounds is based on C—H bond functionalization reactions, in which two simple, unfunctionalized molecules are coupled together with cleavage of a C—H bond and formation of a C—X bond (X=C or heteroatom). This paper reviews the methods for the synthesis of phthalides and α,β-butenolides by C—H bond functionalization from non-halogenated starting materials. Over 30 methods are reported, mostly developed during the past ten years. [ABSTRACT FROM AUTHOR]

Published
2019
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36. ChemInform Abstract: Yonemitsu-Type Condensations Catalyzed by Proline and Eu(OTf)3.

Author

Renzetti, Andrea, Boffa, Emanuela, Colazzo, Marco, Gerard, Stephane, Sapi, Janos, Chan, Tak‐Hang, Nakazawa, Hiroshi, Villani, Claudio, and Fontana, Antonella

Subjects
*PROLINE, *DIASTEREOISOMERS synthesis, *CHEMICAL synthesis, *EUROPIUM compounds synthesis, *CATALYSIS
Abstract

The products are obtained as single diastereomers or as mixtures of diastereomers. [ABSTRACT FROM AUTHOR]

Published
2015
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39. ChemInform Abstract: TiCl4/Et3N‐Promoted Three‐Component Condensation Between Aromatic Heterocycles, Aldehydes, and Active Methylene Compounds.

Author

Renzetti, Andrea, Dardennes, Emmanuel, Fontana, Antonella, De Maria, Paolo, Sapi, Janos, and Gerard, Stephane

Abstract

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Published
2009
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40. Condensation of beta-diester titanium enolates with carbonyl substrates: a combined DFT and experimental investigation.

Author

Marrone A, Renzetti A, De Maria P, Gérard S, Sapi J, Fontana A, and Re N

Subjects
Algorithms, Kinetics, Magnetic Resonance Spectroscopy, Malonates chemistry, Thermodynamics, Aldehydes chemistry, Titanium chemistry
Abstract

The condensation of dialkyl beta-diesters with various aldehydes promoted by TiCl4 has been studied by DFT approaches and experimental methods, including NMR, IR and UV/Vis spectroscopy. Various possible reaction pathways have been investigated and their energy profiles evaluated to find out a plausible mechanism of the reaction. Theoretical results and experimental evidence point to a three-step mechanism: 1) Ti-induced formation of the enolate ion; 2) aldol reaction between the enolate ion and the aldehyde, both coordinated to titanium; and 3) intramolecular elimination that leads to a titanyl complex. The presented mechanistic hypothesis allows one to better understand the pivotal role of titanium(IV) in the reaction.

Published
2009
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