Expansion of a Synthesized Library of N-Benzyl Sulfonamides Derived from an Indole Core to Target Pancreatic Cancer

In an effort to further investigate previously observed activity of indolyl sulfonamides towards pancreatic cancer cell lines, a library of 44 compounds has been synthesized. The biological activity of the compounds has been determined using two different screening assay techniques against 7 pancreatic cancer cell lines and 9 non-pancreatic cancer cell lines. In the first assay, the cytotoxicity of the compounds was evaluated using a traditional (48 hour compound exposure) method. An in silico investigation was conducted to determine if the compounds might be inducing cell death by inhibiting the S100A2-p53 protein-protein interaction. In the second assay, the potential role of the compounds as metabolic inhibitors of ATP production was evaluated using a rapid screening (1-2 hour compound exposure) method. IC50 values of the hit compounds were obtained and four compounds displayed sub-micromolar potency against PANC-1 cells. The investigation has provided several compounds that display selective in vitro activity toward pancreatic cancer that warrant further development.

Synthesis and Biological Evaluation of a Library of Sulfonamide Analogs of Memantine to Target Glioblastoma

A library of 34 lipophilic sulfonamides based upon the memantine core has been synthesized to identify potential drug candidates to cross the blood-brain barrier and target glioblastoma. The library was screened for in vitro activity against 4 mammalian cell lines, including U-87 (glioblastoma). Additional synthetic variation of the active compounds has validated the importance of specific regions of the pharmacophore, with the sulfonamide functionality and S-aryl unit displaying the most significant impact. In silico investigations suggest the active compounds might target DDR1 or RET proteins. The investigation has resulted in several compounds that warrant further development for lead optimization.

Synthesis and biological evaluation of N-alkyl sulfonamides derived from polycyclic hydrocarbon scaffolds using a nitrogen-centered radical approach

Polycyclic hydrocarbons (PH) provide intriguing potential as lipophilic scaffolds within medicinal chemistry, but are currently limited by the availability of synthetic tools for predictable modification of the PH unit. Herein we report the development of new methods for installation of a sulfonamide unit to PH cores. In the first method, a xanthate ester serves as reagent for aminosulfonation using pre-formed imidoiodinane as N-source. An investigation of the reaction mechanism was performed to implicate a process involving a N-centered radical. An additional method for sulfonamide installation is described that involves the use of commercially available reagents and operationally convenient conditions. Using the new synthetic methods, 22 compounds were prepared and screened for biological activity against 6 mammalian cell lines along with Gram-positive and Gram-negative bacterial strains. Results of the viability assays have identified compounds that exhibit higher potency than other known anticancer agents such as indisulam and ABT-751. Additionally, the physicochemical and drug-likeness properties of the synthesized compounds have been determined experimentally and using in silico predictive tools. The initial exploration into sulfonamide insertion into PH cores has resulted in a number of compounds that warrant further development to produce molecules with therapeutic value.

Development of a Rapid In Vitro Screening Assay Using Metabolic Inhibitors to Detect Highly Selective Anticancer Agents

Traditional long exposure (24-72 h) cell viability assays for identification of potential drug compounds can fail to identify compounds that are: (a) biologically active but not toxic and (b) inactive without the addition of a synergistic additive. Herein, we report the development of a rapid (1-2 h) compound screening technique using a commercially available cell viability kit (CellTiter-Glo) that has led to the detection of compounds that were not identified as active agents using traditional cytotoxicity screening methods. These compounds, in combination with metabolic inhibitor 2-deoxyglucose, display selectivity toward a pancreatic cancer cell line. An evaluation of 11 mammalian cell lines against 30 novel compounds and two metabolic inhibitors is reported. The inclusion of metabolic inhibitors during an initial screening process, and not simply during mechanistic investigations of a previously identified hit compound, provides a rapid and sensitive tool for identifying drug candidates potentially overlooked by other methods.

PhI(OAc)2 and iodine-mediated synthesis of N-alkyl sulfonamides derived from polycyclic aromatic hydrocarbon scaffolds and determination of their antibacterial and cytotoxic activities

The development of new approaches toward chemo- and regioselective functionalization of polycyclic aromatic hydrocarbon (PAH) scaffolds will provide opportunities for the synthesis of novel biologically active small molecules that exploit the high degree of lipophilicity imparted by the PAH unit. Herein, we report a new synthetic method for C-X bond substitution that is speculated to operate via a N-centered radical (NCR) mechanism according to experimental observations. A series of PAH sulfonamides have been synthesized and their biological activity has been evaluated against Gram-negative and Gram-positive bacterial strains (using a BacTiter-Glo assay) along with a series of mammalian cell lines (using CellTiter-Blue and CellTiter-Glo assays). The viability assays have resulted in the discovery of a number of bactericidal compounds that exhibit potency similar to other well-known antibacterials such as kanamycin and tetracycline, along with the discovery of a luciferase inhibitor. Additionally, the physicochemical and drug-likeness properties of the compounds were determined experimentally and using in silico approaches and the results are presented and discussed within.

Enhanced Conductivity via Extraction of Hydrocarbon Templates from Nanophase-Separated PEO-LiOTf Polymer Electrolyte Films

A series of poly(ethylene oxide)-LiOTf electrolyte films were prepared using a variety of hydrocarbon templates as nanofillers, resulting in observable nanophase separation in the polymer electrolyte. Upon partial extraction of the nanofiller template, an enhanced conductivity over 2 orders of magnitude was measured using ac impedance. Scanning electron microscopy, differential scanning calorimetry, and thermogravimetric analysis were employed to characterize the porosity, composition, and mass loss of template-extracted and nonextracted film samples.

U.S. Food and Drug Administration-Certified Food Dyes as Organocatalysts in the Visible Light-Promoted Chlorination of Aromatics and Heteroaromatics

Seven FDA-certified food dyes have been investigated as organocatalysts. As a result, Fast Green FCF and Brilliant Blue FCF have been discovered as catalysts for the chlorination of a wide range of arenes and heteroarenes in moderate to excellent yields and high regioselectivity. Mechanistic investigations of the separate systems indicate that different modes of activation are in operation, with Fast Green FCF being a light-promoted photoredox catalyst that is facilitating a one-electron oxidation of N-chlorosuccinimide (NCS) and Brilliant Blue FCF serving as a chlorine-transfer catalyst in its sulfonphthalein form with 1,3-dichloro-5,5-dimethylhydantoin (DCDMH) as stoichiometric chlorine source. Dearomatization of naphthol and indole substrates was observed in some examples using the Brilliant Blue/DCDMH system.

Synthesis and identification of heteroaromatic N-benzyl sulfonamides as potential anticancer agents

Sulfonamides are a crucial class of bioisosteres that are prevalent in a wide range of pharmaceuticals, however, the available methods for their production directly from heteroaryl aldehyde reagents remains surprisingly limited. A new approach for regioselective incorporation of a sulfonamide unit to heteroarene scaffolds has been developed and is reported within. As a result, a variety of primary benzylic N-alkylsulfonamides have been prepared via a two-step (one pot) formation from the in situ reduction of an intermediate N-sulfonyl imine under mild, practical conditions. The compounds have been screened against a variety of cell lines for cytotoxicity effects using a Cell Titer Blue assay. The cell viability investigation identifies a subset of N-benzylic sulfonamides derived from the indole scaffold to be targeted for further development into novel molecules with potential therapeutic value. The most cytotoxic of the compounds prepared, AAL-030, exhibited higher potency than other well-known anticancer agents Indisulam and ABT-751.

Organic Dye-Catalyzed, Visible-Light Photoredox Bromination of Arenes and Heteroarenes Using N-Bromosuccinimide

A variety of arenes and heteroarenes are brominated in good to excellent yields using N-bromosuccinimide (NBS) under mild and practical conditions. According to mechanistic investigations described within, the reaction is speculated to proceed via activation of NBS through a visible-light photoredox pathway utilizing erythrosine B as a photocatalyst. A photo-oxidative approach effectively amplifies the positive polarization on the bromine atom of the NBS reagent. This increase in the electrophilic nature of NBS results in drastically reduced reaction times and diversion from competing light-promoted reactive pathways.

Formation of N-sulfonyl imines from iminoiodinanes by iodine-promoted, N-centered radical sulfonamidation of aldehydes

A light-promoted, non-traditional carbonyl activation via a N-centered radical (NCR) species to produce activated imines using iminoiodinanes is reported.

Visible-light-mediated, nitrogen-centered radical amination of tertiary alkyl halides under metal-free conditions to form α-tertiary amines

A mild and operationally convenient amino-functionalization of a range of tertiary alkyl halides that involves a N,N-diiodosulfonamide reactive species has been developed.

Carboxyl activation via silylthioesterification: one-pot, two-step amidation of carboxylic acids catalyzed by non-metal ammonium salts

The first organo-catalyzed silylthioesterification of a carboxylic acid and a commercially available mercaptoorganosilane results in the in situ production of an O-silylthionoester. Subsequent amine addition forms amides in an operationally simple one-pot procedure without removal of water. The scope and efficiency of these reactions with respect to the catalyst, carboxylic acid, amine, [Si─S] moiety, and solvent are investigated. A number of functionalities are tolerated in the two-step amidation including alkene, alkyne, alkyl and aryl halides, benzylic ethers, and heterocycles with free coordinating sites.

Hydrous zinc halide-catalyzed aminosulfonation of hydrocarbons

Benzylic and allylic hydrocarbons are selectively converted to the corresponding sulfonamides by a ZnBr2-H2O-catalyzed reaction with PhI=NTs; saturated adamantane is aminosulfonated at the tertiary C-H bond.