Hydroesterification of Polycyclooctene to Access Linear Ethylene Ethyl Acrylate Copolymers as a Step Toward Polyolefin Functionalization
Ogbu, Ikechukwu Martin
;
Fastow, Eli J
;
Winey, Karen I
, et al.
Macromolecules,2024,57(22):10767-10777.
DOI:
10.1021/acs.macromol.4c02074
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Abstract: To advance a strategy of polymer-to-polymer upcycling of waste polyolefin by dehydrogenation then functionalization, we report successful hydroesterification of polycyclooctene (PCOE), an analogue for partially unsaturated polyethylene. Here, we convert PCOE to a linear analog for poly(ethylene-co-ethyl acrylate) (EEA) across a range of ethyl acrylate incorporations (0 to 18 mol % of ethylene units). The ester incorporation was well controlled by reaction time, and the remaining C═C bonds were subsequently hydrogenated. The bulky ethyl acrylate groups did not incorporate into orthorhombic PE crystals, decreasing the crystallinity, crystallite size, and melting temperature with increasing functionalization. Additionally, hydroesterification tuned the dynamic mechanical properties, decreasing both the glass transition temperature and the storage modulus in the rubbery regime with greater functionalization. The linear EEA analogs reported here achieve remarkable extensibility (strain > 4000%) and high toughness, comparable to commercial random and branched EEA. Ultimately, we demonstrate successful conversion of an analogue to dehydrogenated PE to a linear EEA with favorable mechanical properties.
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Cy5 Dye Cassettes Exhibit Through-Bond Energy Transfer and Enable Ratiometric Fluorescence Sensing
Zhumin Zhang
;
Jordan L. Chasteen
;
Bradley D. Smith
JOC,2024,89(5):3309-3318.
DOI:
10.1021/acs.joc.3c02767
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Abstract: The chemosensor literature contains many reports of fluorescence sensing using polyaromatic hydrocarbon fluorophores such as pyrene, tetraphenylethylene, or polyaryl(ethynylene), where the fluorophore is excited with ultraviolet light (<400 nm) and emits in the visible region of 400–500 nm. There is a need for general methods that convert these “turn-on” hydrocarbon fluorescent sensors into ratiometric sensing paradigms. One simple strategy is to mix the responsive hydrocarbon sensor with a second non-responsive dye that is excited by ultraviolet light but emits at a distinctly longer wavelength and thus acts as a reference signal. Five new cyanine dye cassettes were created by covalently attaching a pyrene, tetraphenylethylene, or biphenyl(ethynylene) component as the ultraviolet-absorbing energy donor directly to the pentamethine chain of a deep-red cyanine (Cy5) energy acceptor. Fluorescence emission studies showed that these Cy5-cassettes exhibited large pseudo-Stokes shifts and high through-bond energy transfer efficiencies upon excitation with ultraviolet light. Practical potential was demonstrated with two examples of ratiometric fluorescence sensing using a single ultraviolet excitation wavelength. One example mixed a Cy5-cassette with a pyrene-based fluorescent indicator that responded to changes in Cu2+ concentration, and the other example mixed a Cy5-cassette with the fluorescent pH sensing dye, pyranine.
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1227040-87-0 ;
54136-26-4 ;
1195975-05-3 ;
534-17-8 ;
29079-00-3 ;
13965-03-2 ;
3375-31-3 ;
7681-65-4 ;
63149-24-6 ;
64285-36-5
Synthesis and Characterization of 5-(2-Fluoro-4-[11C]methoxyphenyl)-2,2-dimethyl-3,4-dihydro-2H-pyrano[2,3-b]pyridine-7-carboxamide as a PET Imaging Ligand for Metabotropic Glutamate Receptor 2
Yuan, Gengyang
;
Dhaynaut, Maeva
;
Lan, Yu
, et al.
J. Med. Chem.,2022,65(3):2593-2609.
DOI:
10.1021/acs.jmedchem.1c02004
PubMed ID:
35089713
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Abstract: Metabotropic glutamate receptor 2 (mGluR2) is a therapeutic target for several neuropsychiatric disorders. An mGluR2 function in etiology could be unveiled by positron emission tomography (PET). In this regard, 5-(2-fluoro-4-[11C]methoxyphenyl)-2,2-dimethyl-3,4-dihydro-2H-pyrano[2,3-b]pyridine-7-carboxamide ([11C]13, [11C]mG2N001), a potent negative allosteric modulator (NAM), was developed to support this endeavor. [11C]13 was synthesized via the O-[11C]methylation of phenol 24 with a high molar activity of 212 ± 76 GBq/μmol (n = 5) and excellent radiochemical purity (>99%). PET imaging of [11C]13 in rats demonstrated its superior brain heterogeneity and reduced accumulation with pretreatment of mGluR2 NAMs, VU6001966 (9) and MNI-137 (26), the extent of which revealed a time-dependent drug effect of the blocking agents. In a nonhuman primate, [11C]13 selectively accumulated in mGluR2-rich regions and resulted in high-contrast brain images. Therefore, [11C]13 is a potential candidate for translational PET imaging of the mGluR2 function.
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16289-54-6 ;
5521-55-1 ;
22047-25-2 ;
98-80-6 ;
40155-47-3 ;
5720-05-8 ;
879-65-2 ;
98-96-4 ;
31519-62-7 ;
23688-89-3 ;
23611-75-8 ;
33332-25-1 ;
20737-42-2 ;
61442-38-4 ;
17933-03-8 ;
50681-25-9 ;
13924-99-7 ;
40155-43-9 ;
166744-78-1 ;
36070-80-1 ;
4595-61-3 ;
118853-60-4 ;
41110-28-5 ;
40155-42-8 ;
937669-80-2 ;
31462-59-6 ;
16419-60-6 ;
5424-01-1 ;
59-67-6 ;
34604-60-9 ;
27398-39-6 ;
1196151-53-7 ;
19847-12-2 ;
13965-03-2 ;
876161-05-6 ;
27825-21-4 ;
2164-61-6 ;
4604-72-2 ;
98-97-5 ;
24005-61-6 ;
5521-61-9 ;
2516-34-9 ;
2719-27-9 ;
123-90-0 ;
6761-50-8 ;
625-43-4 ;
872-64-0 ;
1309866-36-1 ;
36932-49-7 ;
1528085-68-8 ;
1195533-51-7 ;
13534-79-7
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Structure activity relationship of pyrazinoic acid analogs as potential antimycobacterial agents
Hegde, Pooja V.
;
Aragaw, Wassihun W.
;
Cole, Malcolm S.
, et al.
Bioorgan. Med. Chem.,2022,74,117046.
DOI:
10.1016/j.bmc.2022.117046
PubMed ID:
36228522
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Abstract: Tuberculosis (TB) remains a leading cause of infectious disease-related mortality and morbidity. Pyrazinamide (PZA) is a critical component of the first-line TB treatment regimen because of its sterilizing activity against non-replicating Mycobacterium tuberculosis (Mtb), but its mechanism of action has remained enigmatic. PZA is a prodrug converted by pyrazinamidase encoded by pncA within Mtb to the active moiety, pyrazinoic acid (POA) and PZA resistance is caused by loss-of-function mutations to pyrazinamidase. We have recently shown that POA induces targeted protein degradation of the enzyme PanD, a crucial component of the CoA biosynthetic pathway essential in Mtb. Based on the newly identified mechanism of action of POA, along with the crystal structure of PanD bound to POA, we designed several POA analogs using structure for interpretation to improve potency and overcome PZA resistance. We prepared and tested ring and carboxylic acid bioisosteres as well as 3, 5, 6 substitutions on the ring to study the structure activity relationships of the POA scaffold. All the analogs were evaluated for their whole cell antimycobacterial activity, and a few representative mols. were evaluated for their binding affinity, towards PanD, through isothermal titration calorimetry. We report that analogs with ring and carboxylic acid bioisosteres did not significantly enhance the antimicrobial activity, whereas the alkylamino-group substitutions at the 3 and 5 position of POA were found to be up to 5 to 10-fold more potent than POA. Further development and mechanistic anal. of these analogs may lead to a next generation POA analog for treating TB.
Keywords:
Tuberculosis ;
Pyrazinoic acid ;
pyrazinamide
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16289-54-6 ;
5521-55-1 ;
22047-25-2 ;
98-80-6 ;
40155-47-3 ;
5720-05-8 ;
879-65-2 ;
98-96-4 ;
31519-62-7 ;
23688-89-3 ;
23611-75-8 ;
33332-25-1 ;
20737-42-2 ;
61442-38-4 ;
17933-03-8 ;
50681-25-9 ;
13924-99-7 ;
40155-43-9 ;
36070-80-1 ;
4595-61-3 ;
118853-60-4 ;
41110-28-5 ;
40155-42-8 ;
937669-80-2 ;
98-98-6 ;
31462-59-6 ;
16419-60-6 ;
5424-01-1 ;
59-67-6 ;
34604-60-9 ;
27398-39-6 ;
1196151-53-7 ;
19847-12-2 ;
13965-03-2 ;
876161-05-6 ;
27825-21-4 ;
2164-61-6 ;
4604-72-2 ;
98-97-5 ;
24005-61-6 ;
103-67-3 ;
5521-61-9 ;
2516-34-9 ;
2719-27-9 ;
123-90-0 ;
6761-50-8 ;
625-43-4 ;
872-64-0 ;
36932-49-7 ;
1528085-68-8 ;
1195533-51-7 ;
13534-79-7
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Development of reactive oxygen species (ROS) inhibitors and prodrugs for multiple applications
Senevirathne, Priyangika Prasadini
;
University of Cincinnati,2022.
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Abstract: Reactive oxygen species are a group of highly reactive oxygen-containing entities that are important at a cellular level for multiple biological processes. Low concentrations of ROS can be beneficial as powerful signaling molecules in those biological processes, although excessive concentrations can promote high levels of DNA damage and a variety of diseases such as skin cancer. A newly identified intracellular ROS production source in skin cells is NADPH oxidases. Out of the NOX enzyme family, the NOX1 holoenzyme is most abundantly expressed in the human keratinocyte cells. UV radiation can trigger the activation of NOX1 isoforms which stimulate the assembling of member CYBA and the cytoplasmic protein NOXO1. Inhibition of these enzymes represents a catalytic approach toward reducing ROS for the prevention of ROS inducible diseases. Key disease states include melanoma induced by UV exposure. The first half of the dissertation focuses on investigating new small molecule inhibitors of a key NOX1 holoenzyme to address these challenges. We designed a series of molecules by optimizing the structure of diapocynin and evaluated by in-silico docking methods to determine the binding affinity with NOXO1 cytoplasmic protein (1WLP crystal structure). And have synthesized the series of target molecules for the structure-activity relationship studies. In the first section of the project, we discovered that inhibitor NOX_inh_5 was not cytotoxic, but instead improved the viability of human primary cells from UV exposure, decreased the cellular stress in human skin through the p53 pathway, and reduced the UV-induced DNA damage as monitored by quantification of cyclobutane dimer formation after UV exposure. Then, we characterized the inhibition potential of NOX_inh_5 by using an Isothermal calorimetric (ITC) binding assay and heteronuclear single quantum coherence (HSQC) technique and revealed that the candidate iii molecule can prevent the complex formation of NOXO1 and CYBA membrane protein. In the second section of the project, we did a structure-activity relationship study for the NOX_inh_5 small molecule to optimize the biological characteristics. The last section of the dissertation discussed the development of ROS sensible prodrug to combat the opioid overdose crisis. Here we used oxidative stress conditions caused by opioid overdose to activate the prodrug. Even though opioid antagonist naloxone has a high affinity to bind with opioid receptors to block opioid-induced activation, it is metabolically unstable and has a short half-life of around 33 min. We developed a peroxide-induced prodrug to overcome this issue that can release a steady stream of naloxone. This allows the concentration of naloxone to remain high for longer periods.
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1007-16-5 ;
111-24-0 ;
14221-01-3 ;
99769-19-4 ;
351422-73-6 ;
158407-04-6 ;
1462-37-9 ;
583-61-9 ;
13965-03-2 ;
455-85-6 ;
148893-10-1