29202-20-8Relevant academic research and scientific papers
Quantitative Reactivity Scales for Dynamic Covalent and Systems Chemistry
Zhou, Yuntao,Li, Lijie,Ye, Hebo,Zhang, Ling,You, Lei
supporting information, p. 381 - 389 (2016/01/26)
Dynamic covalent chemistry (DCC) has become a powerful tool for the creation of molecular assemblies and complex systems in chemistry and materials science. Herein we developed for the first time quantitative reactivity scales capable of correlation and prediction of the equilibrium of dynamic covalent reactions (DCRs). The reference reactions are based upon universal DCRs between imines, one of the most utilized structural motifs in DCC, and a series of O-, N-, and S- mononucleophiles. Aromatic imines derived from pyridine-2-carboxyaldehyde exhibit capability for controlling the equilibrium through distinct substituent effects. Electron-donating groups (EDGs) stabilize the imine through quinoidal resonance, while electron-withdrawing groups (EWGs) stabilize the adduct by enhancing intramolecular hydrogen bonding, resulting in curvature in Hammett analysis. Notably, unique nonlinearity induced by both EDGs and EWGs emerged in Hammett plot when cyclic secondary amines were used. This is the first time such a behavior is observed in a thermodynamically controlled system, to the best of our knowledge. Unified quantitative reactivity scales were proposed for DCC and defined by the correlation log K = SN (RN + RE). Nucleophilicity parameters (RN and SN) and electrophilicity parameters (RE) were then developed from DCRs discovered. Furthermore, the predictive power of those parameters was verified by successful correlation of other DCRs, validating our reactivity scales as a general and useful tool for the evaluation and modeling of DCRs. The reactivity parameters proposed here should be complementary to well-established kinetics based parameters and find applications in many aspects, such as DCR discovery, bioconjugation, and catalysis.
A facile one-pot synthesis of 2-(2-pyridyl)quinolines via Povarov reaction
Borel, Carmindo Ribeiro,Barbosa, Luiz Claudio Almeida,Maltha, Célia Regina álvares,Fernandes, Sergio Antonio
supporting information, p. 662 - 665 (2015/01/30)
An efficient synthesis of 2-(2-pyridyl)quinolines was achieved via a three-component Povarov reaction of aromatic aldehydes, anilines, and ethyl vinyl ether under boron trifluoride methyl etherate (BF3·O(CH3)2) acid catalysis. The developed methodology for the preparation of 2-(2-pyridyl)quinolines offers several advantages over previous methods including mild reaction conditions, easy work-up, a wide range of substrate applicability, and products in good yields.
