More Like this

1. Photoinduced peeling of molecular crystals

   https://doi.org/10.1039/c8cc10051a  

   Tong, Fei; Al-Haidar, Maram; Zhu, Lingyan; Al-Kaysi, Rabih O.; Bardeen, Christopher J. (March 2019, Chemical Communications)

   Block-like microcrystals composed of cis -dimethyl-2(3-(anthracen-9-yl)allylidene)malonate are grown from aqueous surfactant solutions. A pulse of 405 nm light converts a fraction of molecules to the trans isomer, creating an amorphous mixed layer that peels off the parent crystal. This photoinduced delamination can be repeated multiple times on the same block. 

   more » « less
2. Synthesis of 2-Arylpyrroles via an Optimized Palladium Coupling

   https://doi.org/10.1055/s-0043-1775453  

   Mitchem, Gunner B; Odom, Aaron L (April 2025, Synthesis)

   Abstract Using response surface methods, we have re-optimized a palladium-catalyzed method for coupling ClZn(pyrrolide) with aryl bromides to selectively generate 2-arylpyrroles. We optimized based on four variables: temperature, ClZn(pyrrolide)/ArBr ratio, catalyst loading, and time. To find a protocol applicable to most substrates of interest, we optimized three different substrates: a bulky arene (mesityl bromide), an electron-rich arene [4-(NMe2)C6H4Br], and an electron-deficient arene [3,5-(CF3)2C6H3Br]. The re-optimized procedures give as good or better yields than the previously published protocols, always in a fraction of the time. In addition, the reactions are generally cleaner with the new conditions, especially with electron-rich substrates, making the products easier to isolate. We applied the conditions to a variety of different substrates in each category, which provided good to excellent isolated yields. 

   more » « less
3. Evidence of Radical Intermediate Generated in the Electrochemical Oxidation of Iodide

   https://doi.org/10.29356/jmcs.v63i3.529  

   Fernando, Ashantha; Parajuli, Suman; Barakoti, Krishna K.; Miao, Wujian; Alpuche Aviles, Mario A (October 2019, Journal of the Mexican Chemical Society)

   null (Ed.)

   We present evidence of the generation of radical ion formation during the oxidation of iodide on a fluorine doped tin oxide (FTO) electrode in acetonitrile. The cyclic voltammograms for the oxidation of iodide and triiodide on FTO are significantly different as in the case of the oxidation of Pt electrode.  These differences are assigned to kinetic differences on the FTO surface that require significant over potentials to drive the oxidation of iodide and triiodide. We propose that at the highly positive potentials the iodine radical intermediate, I·, becomes thermodynamically stable at FTO. The radical nature of the intermediate was verified by the formation of radicals of the usual traps of 5,5-dimethyl-1-pyrroline N-oxide (DMPO) and 2,2,5,5 tetramethyl-1-pyrroline N-oxide (TMPO) when these were added to an electrolyzed solution. Irradiation of an iodine solution causes the homolytic cleavage of I2 and yields the same radical intermediate with TMPO as in the electrolysis experiment. Similar results were obtained from the electrolysis of bromide solutions upon addition of TMPO. Short term electrolysis (< 1 h) gives triiodide as a final product while long-term electrolysis (> 17 h) yields additional byproducts. Byproducts were determined to be organoiodines by gas chromatography-mass spectrometry (GC-MS). Overall, our results are consistent with iodine atoms reacting with the electrolyte during electrolysis at the FTO electrode and with a sequential two-electron transfer process. 

   more » « less
4. Engineering controllable alteration of malonyl-CoA levels to enhance polyketide production

   https://doi.org/10.1038/s41589-025-01911-6  

   Klass, Sarah_H; Wesselkamper, Mia; Cowan, Aidan_E; Lee, Namil; Lanclos, Nathan; Cheong, Seokjung; Wang, Zilong; Chen, Yan; Gin, Jennifer_W; Petzold, Christopher_J; et al (June 2025, Nature Chemical Biology)

   Abstract Heterologous expression of polyketide synthase (PKS) genes inEscherichia colihas enabled the production of various valuable natural and synthetic products. However, the limited availability of malonyl-CoA (M-CoA) inE. coliremains a substantial impediment to high-titer polyketide production. Here we address this limitation by disrupting the native M-CoA biosynthetic pathway and introducing an orthogonal pathway comprising a malonate transporter and M-CoA ligase, enabling efficient M-CoA biosynthesis under malonate supplementation. This approach substantially increases M-CoA levels, enhancing fatty acid and polyketide titers while reducing the promiscuous activity of PKSs toward undesired acyl-CoA substrates. Subsequent adaptive laboratory evolution of these strains provides insights into M-CoA regulation and identifies mutations that further boost M-CoA and polyketide production. This strategy improvesE. colias a host for polyketide biosynthesis and advances understanding of M-CoA metabolism in microbial systems. 

   more » « less
5. Sodium Malonate Inhibits the AcrAB-TolC Multidrug Efflux Pump of Escherichia coli and Increases Antibiotic Efficacy

   https://doi.org/10.3390/pathogens11121409  

   Cauilan, Allea; Ruiz, Cristian (December 2022, Pathogens)

   There is an urgent need to find novel treatments for combating multidrug-resistant bacteria. Multidrug efflux pumps that expel antibiotics out of cells are major contributors to this problem. Therefore, using efflux pump inhibitors (EPIs) is a promising strategy to increase antibiotic efficacy. However, there are no EPIs currently approved for clinical use especially because of their toxicity. This study investigates sodium malonate, a natural, non-hazardous, small molecule, for its use as a novel EPI of AcrAB-TolC, the main multidrug efflux pump of the Enterobacteriaceae family. Using ethidium bromide accumulation experiments, we found that 25 mM sodium malonate inhibited efflux by the AcrAB-TolC and other MDR pumps of Escherichia coli to a similar degree than 50 μΜ phenylalanine-arginine-β-naphthylamide, a well-known EPI. Using minimum inhibitory concentration assays and molecular docking to study AcrB-ligand interactions, we found that sodium malonate increased the efficacy of ethidium bromide and the antibiotics minocycline, chloramphenicol, and ciprofloxacin, possibly via binding to multiple AcrB locations, including the AcrB proximal binding pocket. In conclusion, sodium malonate is a newly discovered EPI that increases antibiotic efficacy. Our findings support the development of malonic acid/sodium malonate and its derivatives as promising EPIs for augmenting antibiotic efficacy when treating multidrug-resistant bacterial infections. 

   more » « less