Autor: Cmoch, Piotr - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Badania tautometrii walencyjnej tetrazol-azydek oraz przegrupowania typu furoksanowego metodami magnetycznego rezonansu jądrowego
Autorzy:: Cmoch, Piotr
Współwytwórcy:: Kamieńska-Trela, Krystyna
Stefaniak, Lech
Wydawca:: Instytut Chemii Organicznej PAN
Institute of Organic Chemistry of Polish Academy of Sciences.
Opis:: 169 pp. : 30 cm +
Praca doktorska. Instytut Chemii Organicznej PAN, 1999
169 s. : 30 cm +
Dissertation, Institute of Organic Chemistry of PAS, 1999
Bibliogr. p. 169
Bibliogr. s. 169
Dostawca treści:: RCIN - Repozytorium Cyfrowe Instytutów Naukowych

Książka

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Skocz do pozycji: 2.

Tytuł:: Anion-Based Self-assembly of Resorcin[4]arenes and Pyrogallol[4]arenes
Autorzy:: Chwastek, Monika
Cmoch, Piotr
Szumna, Agnieszka
Wydawca:: American Chemical Society
Cytata wydawnicza:: ournal of the American Chemical Society 2022, 144 (12), 5350-5358. https://doi.org/10.1021/jacs.1c11793
Opis:: Spatial sequestration of molecules is a prerequisite for the complexity of biological systems, enabling the occurrence of numerous, often non-compatible chemical reactions and processes in one cell at the same time. Inspired by this compartmentalization concept, chemists design and synthesize artificial nanocontainers (capsules and cages) and use them to mimic the biological complexity and for new applications in recognition, separation, and catalysis. Here, we report the formation of large closed-shell species by interactions of well-known polyphenolic macrocycles with anions. It has been known since many years that C-alkyl resorcin[4]arenes (R4C) and C-alkyl pyrogallol[4]arenes (P4C) narcissistically self-assemble in nonpolar solvents to form hydrogen-bonded capsules. Here, we show a new interaction model that additionally involves anions as interacting partners and leads to even larger capsular species. Diffusion-ordered spectroscopy and titration experiments indicate that the anion-sealed species have a diameter of >26 Å and suggest stoichiometry (M)6(X–)24 and tight ion pairing with cations. This self-assembly is effective in a nonpolar environment (THF and benzene but not in chloroform), however, requires initiation by mechanochemistry (dry milling) in the case of non-compatible solubility. Notably, it is common among various polyphenolic macrocycles (M) having diverse geometries and various conformational lability.
National Science Centre (grant SYMFONIA 2016/20/W/ST5/00478 and OPUS 2017/25/B/ST5/01011) Wroclaw Centre for Networking and Supercomputing (grant no. 299)
Dostawca treści:: Repozytorium Centrum Otwartej Nauki

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Skocz do pozycji: 3.

Tytuł:: Synthesis of Pandaroside D from Pandaros acanthifolium via Construction of a Rare Enone System in the Steroid D Ring
Autorzy:: Cmoch, Piotr
Mlynarski, Jacek
Michalak, Karol
Bujok, Robert
Wydawca:: American Chemical Society
Cytata wydawnicza:: Org. Lett. 2025, 27, 9571−9575 // https://doi.org/10.1021/acs.orglett.5c01375
Opis:: All marine saponins isolated from Pandaros acanthifolium feature a unique and distinctive enone system located in the D ring and an unusual cis-C/D ring junction, presenting an intriguing yet unattained synthetic challenge. The first total synthesis of pandaroside D (1) and its methyl ester (2) was achieved from commercially available dehydroisoandrosterone acetate (DHEA). A notable feature of this synthesis is direct oxidation of the C-15 position promoted by the Davis reagent. This concept was applied despite the negative results of such an attempt described in the literature and confirmed the possibility of using the reagent in the direct construction of the enone system in ring D. For the final step, the reaction with sugar trichloroacetimidate proved unpromising; however, glycosylation of synthesized aglycone was successfully achieved using the classical Koenigs–Knorr variant with methyl 2,3,4-tri-O-acetyl-β-d-glucuronate bromide.
Dostawca treści:: Repozytorium Centrum Otwartej Nauki

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Skocz do pozycji: 4.

Tytuł:: Selective transformations of friedelanes isolated from cork smoker wash solids
Autorzy:: Pakulski, Zbigniew
Luboradzki, Roman
Cmoch, Piotr
Yaghoobi Anzabi, Mohadese
Wydawca:: Elsevier
Cytata wydawnicza:: Steroids 201 (2024) 109333 ; https://doi.org/10.1016/j.steroids.2023.109333
Opis:: Friedelin (1) and 3-acetoxyfriedel-3-en-2-one (4), commonly known as friedelane triterpenoids, have been isolated from cork smoker wash solids (also known as black wax) on a multi-gram scale. These compounds are valuable starting materials for the synthesis of new friedelane derivatives. Stereoselective reduction of friedelin by treatment with LiAlH4, sodium, or catalytic hydrogenation results in the formation of both isomers of friedelinol (5 and 7) in excellent yields. Similarly, the reduction of 3-acetoxyfriedel-3-en-2-one gave epi-cerin (14) and a series of isomeric 2,3-diols or α-hydroxyketones. These transformations provide the most straightforward and convenient methods for the synthesis of A-ring functionalised friedelane derivatives using easily accessible starting materials.
Dostawca treści:: Repozytorium Centrum Otwartej Nauki

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Skocz do pozycji: 5.

Tytuł:: Aqueous Micellar Environment Impacts the Co-Catalyzed Phototransformation: A Case Study
Autorzy:: Cmoch, Piotr
Andersson, Martin P.
Gryko, Dorota
Giedyk, Maciej
Wincenciuk, Aleksandra
Wydawca:: American Chemical Society
Cytata wydawnicza:: J. Am. Chem. Soc. 2024, 146, 19828−19838 ; https://doi.org/10.1021/jacs.4c02682
Opis:: In recent years, methodologies that rely on water as the reaction medium have gained considerable attention. The unique properties of micellar solutions were shown to improve the regio-, stereo-, and chemoselectivity of different transformations. Herein, we demonstrate that the aqueous environment is a suitable medium for a visible light driven cobalt-catalyzed reaction involving radical species. In this system, reduced vitamin B12 reacts with alkyl halides, generating radicals that are trapped by the lipophilic olefin present in the Stern layer. A series of NMR measurements and theoretical studies revealed the location of reaction components in the micellar system.
National Science Centre, Poland, grant MAESTRO 2020/38/A/ST4/00185.
Dostawca treści:: Repozytorium Centrum Otwartej Nauki

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Skocz do pozycji: 6.

Tytuł:: Synthesis and cytotoxic activity of 1,2,3-triazoles derived from 2,3-seco-dihydrobetulin via a click chemistry approach
Autorzy:: Cmoch, Piotr
Fiałkowski, Marcin
Kvasnicová, Marie
Bończak, Bartłomiej
Kuczyńska, Kinga
Strnad, Miroslav
Rárová, Lucie
Pakulski, Zbigniew
Wydawca:: Elsevier
Cytata wydawnicza:: Kuczynska, Kinga & Bonczak, Bartlomiej & Rárová, Lucie & Kvasnicová, Marie & Strnad, Miroslav & Pakulski, Zbigniew & Cmoch, Piotr & Fialkowski, Marcin. (2022). Synthesis and cytotoxic activity of 1,2,3-triazoles derived from 2,3-seco-dihydrobetulin via a click chemistry approach. Journal of Molecular Structure. 1250. 131751. https://doi.org/10.1016/j.molstruc.2021.131751
Opis:: In search of new cytotoxic derivatives based on the lupane scaffold, the seco-lupane azides were coupled with a number of alkynes under the 1,3-dipolar cycloaddition (CuAAC) conditions to afford 1,2,3-triazoles. Phenylalkynes having different substituents at the para position were used as starting materials. Similarly, coupling of the seco-lupane thiocyanate with sodium azide gave 5-thiotetrazole. The cytotoxicity of thir- teen derivatives were investigated, as well as the effect of substituents in the phenyl ring on the activity of 1,2,3-triazoles. Limited activity was observed for some of these products. Most of the studied com- pounds were inactive in cancer cell lines and healthy fibroblasts. Triazole 46 exhibited cytotoxic activity against CEM and MCF-7 cancer cell lines, however, it was also toxic to normal human BJ fibroblasts. Two other derivatives – triazole 45 and tetrazole 49 – exhibited low cytotoxicity. Compound 49 showed good selectivity towards tumor cell lines compared to normal fibroblasts. This compound did not affect the growth of normal human fibroblasts and therefore has a wide therapeutic window.
National Science Centre, Poland (grant No. 2016/21/B/ST5/02141) Czech Science Foundation No. 20-25308S.
Dostawca treści:: Repozytorium Centrum Otwartej Nauki

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Skocz do pozycji: 7.

Tytuł:: Supramolecular umpolung: Converting electron-rich resorcin[4]arenes into potent CH-bonding anion receptors and transporters
Autorzy:: Cmoch, Piotr
Danylyuk, Oksana
Szumna, Agnieszka
Chmielewski, Michał J.
Jędrzejewska, Hanna
Mondal, Debashis
Abdurakhmanova, Esma R.
Wydawca:: Elsevier
Cytata wydawnicza:: Chem 10, 1910–1924, June 13, 2024 ; https://doi.org/10.1016/j.chempr.2024.03.003
Opis:: Because of the technological and biological relevance of anions, their receptors and transporters are of great interest in various fields. This study introduces a paradigm shift in design, presenting the traditionally cation-focused resorcin[4]arenes as versatile anion receptors and efficient chloride transporters with remarkable performance in water-rich environments. The design is based on the generation of a large dipole moment, which concentrates the electrostatic potential in a buried binding site, and a seemingly trivial substitution with alkyl chains, which endows the receptors with anion transport capability.
National Science Centre, Poland: grant OPUS 2021/41/B/ST4/01650, grant MINIATURA 2022/06/X/ST4/01360; grant OPUS 2018/31/B/ST5/02085.
CH hydrogen bonding receptors constitute an emerging class of anion sensors and transporters, which, owing to their high proteolytic and pH resistance, are promising for biological applications. CH groups, however, are considered as weak hydrogen bond donors, requiring activation by strongly electron-withdrawing substituents. Accordingly, electron-rich aromatic rings have never been used for this purpose thus far. In this work, we demonstrate that resorcin[4]arenes, well known as p-electron-rich cation receptors, can be converted into CH-bonding anion receptors by simple substitution with four nitro groups. Owing to their unique geometric features, tetranitroresorcin[4]arenes acquire large dipole moments (up to 15.8 D) and highly positive electrostatic potentials at the lower rim, leading to remarkable anion affinities (Ka(Cl-) = 1.36 3 105 M-1 in THF). Moreover, we show also that the seemingly innocent alkyl chains surrounding the anion binding site enable high anion transport activities (EC50 down to 0.012 mol%) and resistance to competitive aqueous/organic media.
Dostawca treści:: Repozytorium Centrum Otwartej Nauki

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Skocz do pozycji: 8.

Tytuł:: In pursuit of cytotoxic triterpenoids. Functionalization of lupane, taraxastane, friedelane, and baccharane derivatives via oxidation with selenium reagents
Autorzy:: Cmoch, Piotr
Kvasnicová, Marie
Gwardiak, Katarzyna
Morzycki, Jacek W.
Kuczyńska, Kinga
Korda, Anna
Jaźwiński, Jarosław
Karczewski, Romuald
Luboradzki, Roman
Strnad, Miroslav
Rárová, Lucie
Pakulski, Zbigniew
Yaghoobi Anzabi, Mohadese
Wydawca:: Elsevier
Cytata wydawnicza:: European Journal of Medicinal Chemistry, 295, 2025, 117770 // https://doi.org/10.1016/j.ejmech.2025.117770
Opis:: A series of triterpenoids of the lupane, taraxastane, friedelane and baccharane type were oxidized using selenium dioxide (SeO2) and benzeneseleninic anhydride (BSA) under various conditions. Depending on the reaction conditions, different reaction pathways were observed, including dehydrogenation, allylic oxidation, and 1,2-diketone formation. In this way, derivatives functionalized in the triterpene core (especially in rings A, D, and E), difficult to obtain by other methods, can be easily prepared. In some cases, rarely observed α-phenylseleno-ketones were isolated. An unexpected reaction involving the cleavage of the carbon-carbon double bond was observed in the presence of stoichiometric amounts of osmium tetroxide. Further transformations of selected intermediates facilitated the synthesis of new, functionally enriched derivatives. The key reaction pathways were investigated using density functional theory (DFT), focusing on bond length variations and transition states, revealing energetically favored pathways and critical transition structures, including covalent and noncovalent interactions. Solvent and isomerization equilibrium effects were proposed to explain the experimentally observed discrepancies. Cytotoxic activity of selected derivatives was investigated. Derivatives 4 and 38 showed strongest cytotoxicity in cancer cells and fibroblasts (IC50 2.6–26.4 μM); some compounds were selective for G-361 or HeLa cells. These results suggest that they may find application in pharmaceuticals.
National Science Centre, Poland 2016/21/B/ST5/02141; Grant Agency of the Czech Republic 23-05474S.
Dostawca treści:: Repozytorium Centrum Otwartej Nauki

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