Quinazolin-4(3H)-ones have been prepared in one step from 2-aminobenzamides and orthoesters in the presence of acetic acid. Simple 2-aminobenzamides were easily converted to the heterocycles by refluxing in absolute ethanol with 1.5 equivalents of the orthoester and 2 equivalents of acetic acid for 12–24 h. Ring-substituted and hindered 2-aminobenzamides as well as cases incorporating an additional basic nitrogen required pressure tube conditions with 3 equivalents each of the orthoester and acetic acid in ethanol at 110 °C for 12–72 h. The reaction was tolerant towards functionality on the benzamide and a range of structures was accessible. Workup involved removal of the solvent under vacuum and either recrystallization from ethanol or trituration with ether-pentane. Several 5,6-dihydropyrimidin-4(3H)-ones were also prepared from 3-amino-2,2-dimethylpropionamide. All products were characterized by melting point, FT-IR, 1H-NMR, 13C-NMR, and HRMS.
Radical-polar crossover mechanisms are invoked in numerous late transition metal and photocatalyzed reactions. To the best of our knowledge, reductive radical-polar crossover mechanisms are not invoked for group 3 early transition metals due to their propensity to exist in high oxidation states. Through use of a redox-active (tris)amido ligand we have accessed this mechanism for use with early transition metals. This mechanism is showcased through enabling product formation for a wide variety of elimination products from α-halo substituted benzylic bromides. The mechanism of this new type of reactivity with Sc is explored, and Hammett analysis reveals an anionic intermediate. The wide functional group tolerance of this reaction is also demonstrated. R adical-polar crossover reactions have emerged as an important mechanistic tool in order to harness both radical and polar chemistry and to overcome limitations of both pathways. 1−3 In catalytic examples, a photocatalyst in the presence of light is generally employed in order to either reduce or oxidize the radical to an anion or cation, respectively (Figure 1a). 2,3 Alternatively, a late transition metal catalyst, such as Cr, can be used to donate or accept the necessary electrons for the crossover to occur. 1,[4][5][6][7]
Radical-polar crossover mechanisms are invoked in numerous late transition metal and photocatalyzed reactions. To the best of our knowledge, reductive radical-polar crossover mechanisms are not invoked for group 3 early transition metals due to their propensity to exist in high oxidation states. Through use of a redox-active (tris)amido ligand we have accessed this mechanism for use with early transition metals. This mechanism is showcased through enabling product formation for a wide variety of elimination products from -halo substituted benzylic bromides. The mechanism of this new type of reactivi-ty with Sc is explored and Hammett analysis reveals an anionic intermediate. The wide functional group tolerance of this reaction is also demonstrated.
Due to the COVID-19 pandemic, the University of Minnesota shifted to a virtual graduate student recruitment weekend. Herein we report on a method to conduct a virtual recruitment weekend using the business communication tool Slack. We discuss our strategy to share both research culture and the departmental culture at the University of Minnesota with prospective students. Content creation, Slack channel curation, and a schedule of events is discussed. Additionally, comparisons to previous years acceptance rates demonstrated that the virtual recruitment weekend acceptance rates were statistically unchanged from previous years, indicating that a virtual recruitment weekend on Slack is as effective as an in-person recruitment weekend. Further advantages for using Slack for increasing diversity and decreasing environmental impacts of graduate recruitment weekends are discussed.<br>
Due to the COVID-19 pandemic, the University of Minnesota shifted to a virtual graduate student recruitment weekend. Herein, we report on a method to conduct a virtual recruitment weekend using the business communication tool Slack. We discuss our strategy to share both research culture and the departmental culture at the University of Minnesota with prospective students. Content creation, Slack channel curation, and a schedule of events are discussed. Additionally, comparisons to previous years’ acceptance rates demonstrated that the virtual recruitment weekend acceptance rates were statistically unchanged from previous years, indicating that a virtual recruitment weekend on Slack is as effective as an in-person recruitment weekend. Further advantages for using Slack for increasing diversity and decreasing environmental impacts of graduate recruitment weekends are discussed.
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