Probing binding and cellular activity of pyrrolidinone and piperidinone small molecules targeting the urokinase receptor

The urokinase receptor (uPAR) is a cell-surface protein that is part of an intricate web of transient and tight protein interactions that promote cancer cell invasion and metastasis. Here, we evaluate the binding and biological activity of a new class of pyrrolidinone and piperidinone compounds, along with derivatives of previously-identified pyrazole and propylamine compounds. Competition assays revealed that the compounds displace a fluorescently labeled peptide (AE147-FAM) with inhibition constant (Ki ) values ranging from 6 to 63 μM. Structure-based computational pharmacophore analysis followed by extensive explicit-solvent molecular dynamics (MD) simulations and free energy calculations suggested the pyrazole-based and piperidinone-based compounds adopt different binding modes, despite their similar two-dimensional structures. In cells, pyrazole-based compounds showed significant inhibition of breast adenocarcinoma (MDA-MB-231) and pancreatic ductal adenocarcinoma (PDAC) cell proliferation, but piperidinone-containing compounds exhibited no cytotoxicity even at concentrations of 100 μM. One pyrazole-based compound impaired MDA-MB-231 invasion, adhesion, and migration in a concentration-dependent manner, while the piperidinone inhibited only invasion. The pyrazole derivative inhibited matrix metalloprotease-9 (gelatinase) activity in a concentration-dependent manner, while the piperidinone showed no effect suggesting different mechanisms for inhibition of cell invasion. Signaling studies further highlighted these differences, showing that pyrazole compounds completely inhibited ERK phosphorylation and impaired HIF1α and NF-κB signaling, while pyrrolidinones and piperidinones had no effect. Annexin V staining suggested that the effect of the pyrazole-based compound on proliferation was due to cell killing through an apoptotic mechanism. The compounds identified represent valuable leads in the design of further derivatives with higher affinities and potential probes to unravel the protein-protein interactions of uPAR

Environmental and Energy Issues in an Open Economy

The environmental and energy consequences of globalization have become an important topic of debate. My dissertation examines the interaction between environmental and energy issues and international trade. Specifically, I investigate environmental regulations and policy in an open economy. In the first chapter, I analyze how an environmental tax on pollution from consumption affects trade flows and welfare in an open economy. In particular, I argue that the effect of an environmental tax on the direction of trade flows depends on who is directly burdened by the regulation (consumers or producers) regardless of who is the polluter. In the case of pollution generated by consumers, a tax on consumers who are the polluters tends to increase exports and reduce imports of dirty goods. This result is the opposite of the well-known effect arising from taxes on pollution-intensive industries. Stringent environmental regulations on pollution-intensive industries diminishes exports and increases imports of dirty industries. In terms of welfare, I show the importance of targeting the policy instrument to the correct source of pollution. Assuming pollution is caused by the consumption of a good, a production tax has a weak effect on increasing welfare through reducing pollution. Furthermore, welfare can fall if the production tax ratio is too high, leading to reduced national income. The second chapter is motivated by recent trends in the U.S. economy: increasing imports from China, decreasing energy consumption, and increasing output. There are two primary theoretical approaches related to the relationship between energy use in U.S. manufacturing and increasing imports from China: Heckscher-Ohlin (H-O) trade theory and the Pollution Haven Hypothesis (PHH). These two frameworks generate opposite predictions about the relationship between these trends. H-O theory suggests that with increased Chinese import penetration, U.S. manufacturing should move toward more energy-intensive industries and as a result, energy use in U.S. industries should increase. Alternatively, PHH predicts that energy-intensive industries in U.S. manufacturing would relocate to other countries with more lax energy regulations. As a result, this would lead U.S. manufacturer to use less energy. To understand the determinants of energy use in U.S. manufacturing, I construct a computable general equilibrium (CGE) model of the U.S. economy using the 2005 input-output table. I find that increasing imports from China causes all manufacturing industries to use more energy. Energy use increases proportional to the output of each industry. However, the magnitude of this effect is very small. In order to help understand the magnitude of the effect, I introduce a (counter-factual) tax on energy use in U.S. manufacturing. Combining these two scenarios, increasing imports from China and an energy tax, produces an outcome consistent with the actual data: decreasing energy consumption and increasing output. Interestingly, total energy use in the U.S. manufacturing sector can decrease while at the same time U.S. welfare can increase due to its improved terms of trade. This result shows that a small energy tax can offset the increased energy use caused by Chinese import penetration, but will not reduce welfare. In addition, unlike the prediction generated by H-O theory, increasing Chinese imports causes imported intermediate inputs from China to become cheaper resulting in increased output in all sectors of U.S. manufacturing. In the final chapter, I numerically estimate these effects using U.S. manufacturing industry-level panel data from 1997 to 2005. I decompose the effect of increasing imports from China on energy use in U.S. manufacturing into a factor substitution effect and an output scale effect. Because import penetration may be endogenous, I instrument for Chinese import penetration using Chinese share of world trade. My results indicate that increasing imports from China raises consumption of fuel and electricity. As in the simulation model, the marginal effect of Chinese import penetration is small, about 0.05% to 0.08%, but statistically significant. Interestingly, the directions of the factor substitution effects on fuel and electricity are opposite. Increasing imports from China causes a decrease in the factor ratio of fuel over labor, but an increase in the ratio of electricity over labor

A One-Pot Synthesis of Pyranone and Pyrrole Derivatives from β‑Chlorovinyl Ketones via Direct Conjugate Addition Approach

The direct conjugate addition reactions of imino esters to β-chlorovinyl ketones have been accomplished in the presence of a substoichiometric amount of hard base, LiHMDS. An <i>in situ</i> generated species from the conjugate addition reaction readily acted as autocatalyst to convert the imino esters to its corresponding enolates. By utilizing a sequence of conjugate addition/elimination/lactonization followed by either reduction or reaction with amines, the novel one-pot syntheses of highly functionalized pyranone and pyrrole derivatives were accomplished in good to excellent yields

A Facile Access to 4‑Substituted-2-naphthols via a Tandem Friedel–Crafts Reaction: A β‑Chlorovinyl Ketone Pathway

A one-pot synthesis of 2-naphthol derivatives is accomplished using a tandem Friedel–Crafts reaction sequence. The developed methodology allows for a concomitant construction of up to three C–C bonds between readily available alkynes and phenylacetyl chloride derivatives by an intermolecular Friedel–Crafts acylation of alkynes followed by an intramolecular Friedel–Crafts alkylation of β-chlorovinyl ketone intermediates

1,3-Dienones and 2<i>H</i>‑Pyran-2-ones from Soft α‑Vinyl Enolization of β‑Chlorovinyl Ketones: Defined Roles of Brönsted and Lewis Base

The eliminative reaction pathways of (<i>E</i>)-β-chlorovinyl ketones were investigated in the presence of both Brönsted and Lewis bases. The Brönsted base, Et₃N, effected the soft α-vinyl enolization of (<i>E</i>)-β-chlorovinyl ketones to [3]­cumulenol intermediates; in turn, a catalytic amount of Lewis base, PPh₃, initiated isomerization to provide 1,3-dienones in high yields. The introduction of a carbon-based nucleophile into the reaction mixture provided the highly efficient synthetic route to 2<i>H</i>-pyran-2-ones in one pot, where the carbon-based nucleophile generated by an extra equivalent of Brönsted base, Et₃N, attacked the electrophilic [3]­cumulenol intermediates to initiate cyclization to give 2<i>H</i>-pyran-2-ones

One-Pot Tandem Nickel-Catalyzed α‑Vinyl Aldol Reaction and Cycloaddition Approach to [1,2,3]Triazolo[1,5‑<i>a</i>]quinolines

A one-pot tandem approach to [1,2,3]triazolo[1,5-a]quinolines was developed from (E)-β-chlorovinyl ketones and 2-azidoaryl carbonyls using a sequence of α-vinyl aldol and azide–alkyne cycloaddition reactions. In particular, the intramolecular azide–alkyne cycloaddition of allenol intermediates was readily promoted by a synergistic action of NEt3 and nickel catalysts. Given that the [1,2,3]triazolo[1,5-a]quinolines are useful synthetic precursors to α-diazoimines through ring–chain isomerization process, the subsequent denitrogenative transformations should provide ready access to valuable heterocyclic compounds

Silver-Catalyzed Asymmetric Desymmetrization of Cyclopentenediones via [3 + 2] Cycloaddition with α‑Substituted Isocyanoacetates

A highly selective and practical asymmetric Ag­(I) catalyst system has been developed for the [3 + 2] cycloaddition reactions between isocyanoacetates and cyclopentenediones. The current Ag­(I) catalyst system tolerates moisture and air and readily utilizes class III solvents such as EtOAc and acetone. The development of <i>on demand</i> generation of an active chiral catalyst in the presence of isocyanides paves a way to the efficient asymmetric preparation of bicyclic pyrrolidines with four stereogenic centers, including two quaternary centers in 80–97% ee

<i>o</i>‑Naphthoquinone-Catalyzed Aerobic Oxidation of Amines to (Ket)imines: A Modular Catalyst Approach

A modular aerobic oxidation of amines to imines has been achieved using an <i>ortho</i>-naphtho­quinone (<i><b>o</b></i><b>-NQ</b>) catalyst. The cooperative catalyst system of <i><b>o</b></i><b>-NQ</b> and Cu­(OAc)₂ enabled the formation of homocoupled imines from benzylamines, while the presence of TFA helped the formation of cross-coupled imines in excellent yields. The current mild aerobic oxidation protocol could also be applied to the oxidation of secondary amines to imines or ketimines with the help of cocatalyst, Ag₂CO₃, with excellent yields

Direct Acyl Radical Addition to 2<i>H</i>‑Indazoles Using Ag-Catalyzed Decarboxylative Cross-Coupling of α‑Keto Acids

A direct acyl radical addition to 2<i>H</i>-indazoles has been achieved for the first time, where the less-aromatic <i>quinonoid</i> 2<i>H</i>-indazoles readily accepted radical species to the C-3 position. Motivated by the lack of direct acylation strategy for 2<i>H</i>-indazoles, the current method utilizes the radical acceptability of 2<i>H</i>-indazoles, discovering an ambient temperature reaction to provide facile access to a diverse array of 3-acyl-2<i>H</i>-indazoles with three points of structural diversification in 25%–83% yields