Browsing by Subject "Suzuki-Miyaura cross-coupling"

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  • Bulatov, Evgeny; Lahtinen, Elmeri; Kivijärvi, Lauri; Hey-Hawkins, Evamarie; Haukka, Matti (2020)
    Selective laser sintering (SLS) 3d printing was utilized to manufacture a solid catalyst for Suzuki-Miyaura cross-coupling reactions from polypropylene as a base material and palladium nanoparticles on silica (SilicaCat Pd(0)R815-100 by SiliCycle) as the catalytically active additive. The 3d printed catalyst showed similar activity to that of the pristine powdery commercial catalyst, but with improved practical recoverability and reduced leaching of palladium into solution. Recycling of the printed catalyst led to increase of the induction period of the reactions, attributed to the pseudo-homogeneous catalysis. The reaction is initiated by oxidative addition of aryl iodide to palladium nanoparticles, resulting in formation of soluble molecular species, which then act as the homogeneous catalyst. SLS 3d printing improves handling, overall practicality and recyclability of the catalyst without altering the chemical behaviour of the active component.
  • Tamminen, Matti (Helsingfors universitet, 2016)
    Membrane-bound pyrophosphatases (mPPases) are a potential target for drugs against many neglected protozoan diseases, such as malaria, leishmaniasis, toxoplasmosis and trypanosomiasis. New drugs against these diseases are urgently needed, as the clinically used ones are either not effective, suffer from side effects, or resistance against them is developing. The mPPases of these protozoans are genetically conserved, while mammalian DNA does not encode them. A drug development project to find mPPase inhibitors was started, based on mPPase structures solved through X-Ray crystallography. Four hit compounds were identified. The aim of this study was to investigate the binding of these hit compounds at the mPPase binding site, and based on these results, to develop and synthesize novel compounds with higher affinity. A hit compound with an isoxazole ring was chosen as the model compound to be developed further. These novel compounds were evaluated by docking them into the binding site. Eight compounds were chosen to be synthesized and four to be purchased. The Suzuki-Miyaura cross-coupling reaction was used to couple the isoxazole core to different aromatic substituents, producing 3,5-disubstituted isoxazoles. The reactions mostly succeeded, but the yields were uniformly low. Developing the reaction using different solvents and reaction conditions did not produce clear results. Thirteen compounds were tested for activity, including an intermediate product of the synthesis. Two of the compounds showed increased inhibition activity compared to the hit compound, with approximated IC50 values of 10 and 40 μM, respectively. The knowledge gained from these studies can be used to further develop more efficient inhibitors.