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Articles 1 - 15 of 15

Full-Text Articles in Chemistry

Synthesis Of 2-Arylpyridines By The Suzuki–Miyaura Cross-Coupling Of Pyfluor With Hetero (Aryl) Boronic Acids And Esters, Juan Rueda-Espinosa, Dewni Ramanayake, Nicholas Ball, Jennifer A. Love Aug 2023

Synthesis Of 2-Arylpyridines By The Suzuki–Miyaura Cross-Coupling Of Pyfluor With Hetero (Aryl) Boronic Acids And Esters, Juan Rueda-Espinosa, Dewni Ramanayake, Nicholas Ball, Jennifer A. Love

Pomona Faculty Publications and Research

The Suzuki–Miyaura cross-coupling of pyridine-2-sulfonyl fluoride (PyFluor) with hetero(aryl) boronic acids and pinacol boronic esters is reported. The reactions can be performed using Pd(dppf)Cl2 as the catalyst, at temperatures between 65 and 100 °C and in the presence of water and oxygen. This transformation generates 2-arylpyridines in modest to good yields (5%–89%).


Calcium Bistriflimide-Mediated Sulfur (Vi)–Fluoride Exchange (Sufex): Mechanistic Insights Toward Instigating Catalysis, Nicholas Ball, Brian Han, Samuel R. Khasnavis, Matthew Nwerem, Michael Bertagna, O Maduka Ogba Jun 2022

Calcium Bistriflimide-Mediated Sulfur (Vi)–Fluoride Exchange (Sufex): Mechanistic Insights Toward Instigating Catalysis, Nicholas Ball, Brian Han, Samuel R. Khasnavis, Matthew Nwerem, Michael Bertagna, O Maduka Ogba

Pomona Faculty Publications and Research

We report a mechanistic investigation of calcium bistriflimide-mediated sulfur(VI)–fluoride exchange (SuFEx) between sulfonyl fluorides and amines. We determine the likely pre-activation resting state─a calcium bistriflimide complex with ligated amines─thus allowing for corroborated calculation of the SuFEx activation barrier at ∼21 kcal/mol, compared to 21.5 ± 0.14 kcal/mol derived via kinetics experiments. Transition state analysis revealed: (1) a two-point calcium-substrate contact that activates the sulfur(VI) center and stabilizes the leaving fluoride and (2) a 1,4-diazabicyclo[2.2.2]octane additive that provides Brønsted-base activation of the nucleophilic amine. Stable Ca–F complexes upon sulfonamide formation are likely contributors to inhibited catalytic turnover, and a proof-of-principle redesign …


Sulfondiimidamides Unlocked As New S(Vi) Hubs For Synthesis And Drug Discovery, Nicholas Ball Mar 2022

Sulfondiimidamides Unlocked As New S(Vi) Hubs For Synthesis And Drug Discovery, Nicholas Ball

Pomona Faculty Publications and Research

Despite their promise as drug targets, access to nitrogen-rich S(VI) compounds has been a significant synthetic challenge. In this issue of Chem, Zhang and Willis explore a new class of S(VI) compounds-sulfondiimidamides-providing robust strategies toward their synthesis, derivation, and promise as new sulfonamide bioisosteres.


The Emerging Applications Of Sulfur (Vi) Fluorides In Catalysis, Nicholas Ball, Cayo Lee, Jonathan E. Elisabeth, Nathan C. Friede, Glenn M. Sammis May 2021

The Emerging Applications Of Sulfur (Vi) Fluorides In Catalysis, Nicholas Ball, Cayo Lee, Jonathan E. Elisabeth, Nathan C. Friede, Glenn M. Sammis

Pomona Faculty Publications and Research

The past decade has witnessed remarkable growth of catalytic transformations in organic sulfur(VI) fluoride chemistry. This Perspective concentrates exclusively on foundational examples that utilize catalytic strategies to synthesize and react S(VI) fluorides. Key mechanistic studies that aim to provide insight toward future catalytic systems are emphasized.


Sufex Activation With Ca(Ntf2)2: A Unified Strategy To Access Sulfamides, Sulfamates, And Sulfonamides From S(Vi) Fluorides, Nicholas Ball, Subham Mahapatra, Cristian P. Woroch, Todd W. Butler, Sabrina N. Carneiro, Sabrina C. Kwan, Samuel R. Khasnavis, Junha Gu, Jason K. Dutra, Beth C. Vetelino, Justin Bellenger, Christopher W. Am Ende May 2020

Sufex Activation With Ca(Ntf2)2: A Unified Strategy To Access Sulfamides, Sulfamates, And Sulfonamides From S(Vi) Fluorides, Nicholas Ball, Subham Mahapatra, Cristian P. Woroch, Todd W. Butler, Sabrina N. Carneiro, Sabrina C. Kwan, Samuel R. Khasnavis, Junha Gu, Jason K. Dutra, Beth C. Vetelino, Justin Bellenger, Christopher W. Am Ende

Pomona Faculty Publications and Research

A method to activate sulfamoyl fluorides, fluorosulfates, and sulfonyl fluorides with calcium triflimide and DABCO for SuFEx with amines is described. The reaction was applied to a diverse set of sulfamides, sulfamates, and sulfonamides at room temperature under mild conditions. Additionally, we highlight this transformation to parallel medicinal chemistry to generate a broad array of nitrogen-based S(VI) compounds.


Sulfonamide Synthesis Via Calcium Triflimide Activation Of Sulfonyl Fluorides, Nicholas Ball, Paramita Mukherjee, Cristian P. Woroch, Leah Cleary, Mark Rusznak, Ryan W. Franzese, Matthew R. Reese, Joseph W. Tucker, John M. Humphrey, Sarah M. Etuk, Sabrina C. Kwan, Christopher W. Am Ende Jun 2018

Sulfonamide Synthesis Via Calcium Triflimide Activation Of Sulfonyl Fluorides, Nicholas Ball, Paramita Mukherjee, Cristian P. Woroch, Leah Cleary, Mark Rusznak, Ryan W. Franzese, Matthew R. Reese, Joseph W. Tucker, John M. Humphrey, Sarah M. Etuk, Sabrina C. Kwan, Christopher W. Am Ende

Pomona Faculty Publications and Research

A method using calcium triflimide [Ca(NTf2)2] as a Lewis acid to activate sulfonyl fluorides toward nucleophilic addition with amines is described. The reaction converts a wide array of sterically and electronically diverse sulfonyl fluorides and amines into the corresponding sulfonamides in good yield.


Pd-Catalyzed Conversion Of Aryl Iodides To Sulfonyl Fluorides Using So2 Surrogate Dabso And Selectfluor, Nicholas Ball, Ariana L. Tribby, Ismerai Rodríguez, Shamira Shariffudin Feb 2017

Pd-Catalyzed Conversion Of Aryl Iodides To Sulfonyl Fluorides Using So2 Surrogate Dabso And Selectfluor, Nicholas Ball, Ariana L. Tribby, Ismerai Rodríguez, Shamira Shariffudin

Pomona Faculty Publications and Research

A one-pot Pd-catalyzed conversion of aryl iodide to aryl sulfonyl fluorides using DABSO and Selectfluor has been developed generating aryl sulfonyl fluorides in good to excellent yields. The reaction results in the generation of electronically and sterically diverse sulfonyl fluorides. Additionally, sulfonyl fluorides can be converted to aryl sulfonamides and sulfonic esters using Cs2CO3 under mild conditions.


Small Molecule Inhibitor Design For Anaplastic Lymphoma Kinase Inhibition, Theodore D. Hansel, David J. Grabovsky Oct 2015

Small Molecule Inhibitor Design For Anaplastic Lymphoma Kinase Inhibition, Theodore D. Hansel, David J. Grabovsky

Interface Compendium of Student Work

The Anaplastic Lymphoma Kinase (ALK) gene has been linked to tumorigenesis in a number of human cancers, including anaplastic large cell lymphoma (ALCL) and neuroblastoma. While ALK mutations in ALCL and many other cancers occur as a result of gene fusions with wild type kinase domains, those in neuroblastoma stem from single nucleotide polymorphisms (SNPs) in the kinase domain. These lead to autophosphorylation and constitutive signaling by ALK for cell growth and division, ultimately causing cancer. Crizotinib, an ATP-competitive ALK inhibitor, has proven to be an effective inhibitor of both ALKWT and ALKMutant kinase domains, and is in the middle …


Big Horned, Juniper Harrower Feb 2014

Big Horned, Juniper Harrower

The STEAM Journal

Tinta y tinto (Spanish for black ink and red wine)
Through a process of oxidation, reduction, and light manipulation, Juniper stains and colors paper with red wine and a rich black pigment made of the wild harvested mushroom Coprinopsis atramentaria.


Nature's Assembly Line Logic For Natural Products, Christopher T. Walsh, Ryan G. Kruger, David A. Vosburg Jan 2005

Nature's Assembly Line Logic For Natural Products, Christopher T. Walsh, Ryan G. Kruger, David A. Vosburg

All HMC Faculty Publications and Research

Nature fashions a very large number of diverse products (molecular weights ranging from ca. 200 to 2000 daltons) from simple monomeric metabolites used in primary metabolism. These include polyketide scaffolds generated from the simple C₃ malonyl CoA and C₄ methylmalonyl CoA monomers and nonribosomal peptides made from both the 20 proteinogenic amino acids and dozens of nonpoteinogenic amino acids.¹ A large family of terpenoid skeletons are built from the Δ²- and Δ³-alkene isomers of the biological isoprene monomer, isoprenyl-pyrophosphate.²


A Theoretical Investigation Of Charge Transfer In Several Substituted Acridinium Ions, Jason Lappe '00, Robert J. Cave, Marshall D. Newton, I.V. Rostov Jan 2005

A Theoretical Investigation Of Charge Transfer In Several Substituted Acridinium Ions, Jason Lappe '00, Robert J. Cave, Marshall D. Newton, I.V. Rostov

All HMC Faculty Publications and Research

We present calculations for various properties of the ground and excited states of several arylamine-substituted acridinium ion systems that have been studied experimentally. Using ab initio and semiempirical quantum mechanical methods together with the generalized Mulliken−Hush (GMH) model, we examine the excitation energies, dipole moment shifts, and electronic coupling elements for the vertical charge shift (CSh) processes in these systems. We also examine solvent effects on these properties using a dielectric continuum reaction field model. The results are in generally good agreement with available experimental results and indicate that there is strong electronic coupling in these systems over a wide …


Theoretical Investigation Of The Ground And Excited States Of Coumarin 151 And Coumarin 120, Robert J. Cave, Kieron Burke, Edward W. Castner Jr. Jan 2002

Theoretical Investigation Of The Ground And Excited States Of Coumarin 151 And Coumarin 120, Robert J. Cave, Kieron Burke, Edward W. Castner Jr.

All HMC Faculty Publications and Research

We present calculations of various properties of the ground and excited states of Coumarins 151 and 120. These and related coumarins are important in investigating ultrafast solvation processes in liquids and complex solutions as well as being important acceptors in model electron-transfer systems. We calculate the following:  (1) the electronic excitation energies to several low-lying singlet states, (2) ground and excited-state dipole moments, (3) solvation effects on excitation energies, and (4) the properties of single Coumarin 151-water complexes. We test our Time-Dependent Density Functional Theory (TDDFT) calculations against CASSCF, CASPT2 (both single and multistate versions), CIS, and ZINDO. Using TDDFT, …


Multistate Effects In Calculations Of The Electronic Coupling Element For Electron Transfer Using The Generalized Mulliken−Hush Method, Michael Rust '01, Jason Lappe '00, Robert J. Cave Jan 2002

Multistate Effects In Calculations Of The Electronic Coupling Element For Electron Transfer Using The Generalized Mulliken−Hush Method, Michael Rust '01, Jason Lappe '00, Robert J. Cave

All HMC Faculty Publications and Research

A simple diagnostic is developed for the purpose of determining when a third state must be considered to calculate the electronic coupling element for a given pair of diabatic states within the context of the generalized Mulliken−Hush approach (Chem. Phys. Lett. 1996, 275, 15−19). The diagnostic is formulated on the basis of Löwdin partitioning theory. In addition, an effective 2-state GMH expression is derived for the coupling as it is modified by the presence of the third state. Results are presented for (i) a model system involving charge transfer from ethylene to methaniminium cation, (ii) a …


Time-Dependent Density Functional Theory Investigation Of The Ground And Excited States Of Coumarins 102, 152, 153, And 343, Robert J. Cave, Edward W. Castner Jr. Jan 2002

Time-Dependent Density Functional Theory Investigation Of The Ground And Excited States Of Coumarins 102, 152, 153, And 343, Robert J. Cave, Edward W. Castner Jr.

All HMC Faculty Publications and Research

We present calculations of various properties of the ground and excited electronic states of coumarins 102, 152, 153, and 343. Using density functional theory (DFT) and time-dependent density functional theory (TDDFT), we examine the excitation energies to the S1 and S2 states, the ground and excited-state dipole moments, and the lowest ionization potentials of these coumarins. In the case of C153, we locate two distinct S0 minima due to differing conformations of the julolidyl ring structure and compare properties for the syn and anti conformers. For C343, we examine the possibility of proton transfers in the ground …


On The Vertical And Adiabatic Excitation Energies Of The 21a(G), State Of Trans-1,3-Butadiene, Jason Lappe '00, Robert J. Cave Jan 2000

On The Vertical And Adiabatic Excitation Energies Of The 21a(G), State Of Trans-1,3-Butadiene, Jason Lappe '00, Robert J. Cave

All HMC Faculty Publications and Research

The excitation energy to the 21Ag state of trans-1,3-butadiene is examined using a variety of ab initio electronic structure techniques. While analogous states have been shown to be the lowest singlet excited states for all longer polyenes, for butadiene the position of the 21Ag state relative to the HOMO → LUMO excitation (11Bu) has been difficult to establish theoretically. We employ a variety of methods (CASSCF, CASPT2, MRSDCI, QDVPT) to examine both the vertical and adiabatic excitation energies for this state. At the ground-state geometry, the vertical excitation energies …