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Maftei C.V.,TU Braunschweig | Fodor E.,TU Braunschweig | Jones P.G.,TU Braunschweig | Franz M.H.,InnoChemTech GmbH | And 3 more authors.
Beilstein Journal of Organic Chemistry | Year: 2013

Taking into consideration the biological activity of the only natural products containing a 1,2,4-oxadiazole ring in their structure (quisqualic acid and phidianidines A and B), the natural product analogs 1-(4-(3-tert-butyl-1,2, 4-oxadiazol-5-yl)phenyl)pyrrolidine-2,5-dione (4) and 1-(4-(3-tert-butyl-1,2,4- oxadiazol-5-yl)phenyl)-1H-pyrrole-2,5-dione (7) were synthesized starting from 4-(3-tertbutyl-1,2,4-oxadiazol-5-yl)aniline (1) in two steps by isolating the intermediates 4-(4-(3-tert-butyl-1,2,4-oxadiazol-5-yl)phenylamino)-4-oxobutanoic acid (3) and (Z)-4-(4-(3-tert-butyl-1,2,4-oxadiazol-5-yl)phenylamino)-4-oxobut- 2-enoic acid (6). The two natural product analogs 4 and 7 were then tested for antitumor activity toward a panel of 11 cell lines in vitro by using a monolayer cell-survival and proliferation assay. Compound 7 was the most potent and exhibited a mean IC50 value of approximately 9.4 μM. Aniline 1 was synthesized by two routes in one-pot reactions starting from tert-butylamidoxime and 4-aminobenzoic acid or 4-nitrobenzonitrile. The structures of compounds 1, 2, 4, 5 and 6 were confirmed by X-ray crystallography. © 2013 Maftei et al; licensee Beilstein-Institut. Source


Maftei C.V.,TU Braunschweig | Maftei C.V.,Institutul National Of Cercetare Dezvoltare Pentru Electrochimie Si Materie Condensata | Fodor E.,TU Braunschweig | Fodor E.,Institutul National Of Cercetare Dezvoltare Pentru Electrochimie Si Materie Condensata | And 9 more authors.
European Journal of Medicinal Chemistry | Year: 2015

This work presents the synthesis, characterization and application of eleven new gold (I) complexes 13-23 with 1,2,4-oxadiazole-containing N-heterocyclic carbene (NHC) ligands and of the NHC silver(I) complex 24. The 1,2,4-oxadiazole unit, which can be found in a variety of biologically active natural products such as phidianidines or quisqualic acid, was incorporated, along with a variety of other biologically active moieties (anthracene, indole, 2-pyridine, 2,3,4,5-tetra-O-acetyl-D-glucopyranose, quincorine and quincoridine), in order to change the lipophilicity of the complexes, so that the transport of the active units (M-NHC) though the cell wall barrier is facilitated. The biological activity of the complexes was investigated. In vitro assessment of anti-tumor activity in a panel of 12 human tumor cell lines by a monolayer assay revealed impressive potency (mean IC50 < 0.1 μM) and tumor selectivity for 6 compounds, with individual IC50 values in the low nanomolar range. The solid state structures of compounds 13, 14, 15, 17, 18, 19 and 24 were determined by X-ray diffraction analyses. © 2015 Elsevier Masson SAS. Source


Maftei E.,TU Braunschweig | Maftei E.,Institutul National Of Cercetare Dezvoltare Pentru Electrochimie Si Materie Condensata | Maftei C.V.,TU Braunschweig | Maftei C.V.,Institutul National Of Cercetare Dezvoltare Pentru Electrochimie Si Materie Condensata | And 9 more authors.
Helvetica Chimica Acta | Year: 2016

This work presents the synthesis, characterization, and application of several new metal(I) complexes with trifluoromethylpyridine-containing N-heterocyclic carbene (NHC) ligands. The metal of choice was gold(I) for compounds 7 – 10, rhodium(I) for 11 – 12, and iridium(I) for 13 – 14, respectively. The trifluoromethylpyridine moiety was incorporated, along with other biologically active moieties, with the intention of modifying the lipophilicity of the complexes, so that the transport of the active units (M–NHC) through the cell wall barrier is facilitated. The biological activity of the complexes was investigated. In vitro assessment of antitumor activity in a panel of 12 human tumor cell lines by a monolayer assay revealed good potency (mean IC5012.6 μm) and tumor selectivity for one compound. The solid-state structures of two solvates of compound 7, one with MeOH and one with THF, were determined by X-ray diffraction analysis. © 2016 Verlag Helvetica Chimica Acta AG, Zürich Source


Maftei C.V.,TU Braunschweig | Maftei C.V.,Institutul National Of Cercetare Dezvoltare Pentru Electrochimie Si Materie Condensata | Fodor E.,TU Braunschweig | Fodor E.,Institutul National Of Cercetare Dezvoltare Pentru Electrochimie Si Materie Condensata | And 6 more authors.
Pure and Applied Chemistry | Year: 2015

New chiral derivatives of 15,35,55,75-tetra-tert-butyl-1,3,5,7(1,3)-tetrabenzenacyclooctaphane-12,32,52,72-tetraol [(1); tert-butyl-calix[4]-arene] were synthesized by coupling modified chiral quinuclidines derived from the natural-product-based alkaloids quincorine and quincoridine with the calix[4]arene 1 via either an ester bond or an amide bond. X-ray analyses of two products were performed. Applications of the products in asymmetric catalytic hydrogen transfer reactions are described. A protocol is presented to multi-substitute calix[4]arene at the methylene bridges, resulting in, e.g., 2,6-carboxyl-all-tert-butyl all-methoxy-calix[4]arene. © 2015 IUPAC & De Gruyter. Source


Maftei C.V.,TU Braunschweig | Maftei C.V.,Institutul National Of Cercetare Dezvoltare Pentru Electrochimie Si Materie Condensata | Fodor E.,TU Braunschweig | Fodor E.,Institutul National Of Cercetare Dezvoltare Pentru Electrochimie Si Materie Condensata | And 9 more authors.
Tetrahedron | Year: 2016

The design, structural characterization and potential medical application of novel 1,2,4-oxadiazole and trifluoromethylpyridine derivatives are described. Starting from two readily available compounds, 4-(3-(tert-butyl)-1,2,4-oxadiazol-5-yl)aniline (1) and 2-(3-chloro-5-(trifluoromethyl)pyridin-2-yl)ethanamine (10), other bioactive moieties were incorporated (such as pyrazole, pyrazolo[3,4-d]pyrimidine), in order to modify the lipophilicity of the molecules, so that the transport of the bioactive units though the cell wall barrier could be improved. In vitro anti-cancer activity of these compounds was assessed by a monolayer proliferation assay in a panel of 12 cell lines. A good potency was found for 17, which exhibited a mean IC50 value of 5.66 μM, while the other compounds exhibit minor or no activity. The solid state structures of compounds 3, 5, 7-9, 11, 12 and 17 were established by X-ray diffraction analyses. © 2016 Elsevier Ltd. All rights reserved. Source

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