A series of novel pyridine-annelated spirooxindole-3,2′-pyrrolidines was prepared via 1,3-cycloaddition reaction involving N-methylmaleimide as 1,3-dipolarophile and the appropriate azomethine ylide. The latter 1,3-dipolar species were generated in situ via decarboxylative condensation reaction of the particular α-amino acid with pyridine-annelated isatin in aqueous methanol under reflux. The structures of these new spirooxindole cycloadducts are based on microanalytical, spectral (IR, HRMS, and NMR), and X-ray crystal data.

A series of novel pyridine-annelated spirooxindole-3,2′-pyrrolidines was prepared via 1,3-cycloaddition reaction involving N-methylmaleimide as 1,3-dipolarophile and the appropriate azomethine ylide. The latter 1,3-dipolar species were generated in situ via decarboxylative condensation reaction of the particular α-amino acid with pyridine-annelated isatin in aqueous methanol under reflux. The structures of these new spirooxindole cycloadducts are based on microanalytical, spectral (IR, HRMS, and NMR), and X-ray crystal data.

A series of novel pyridine-annelated spirooxindole-3,20 -pyrrolidines was prepared via 1,3-cycloaddition reaction involving N-methylmaleimide as 1,3- dipolarophile and the appropriate azomethine ylide. The latter 1,3-dipolar species were generated in situ via decarboxylative condensation reaction of the particular aamino acid with pyridine-annelated isatin in aqueous methanol under reflux. The structures of these new spirooxindole cycloadducts are based on microanalytical, spectral (IR, HRMS, and NMR), and X-ray crystal data

Aseriesofnovelpyridine-annelatedspirooxindole-3,20-pyrrolidines was prepared via 1,3-cy-cloaddition reaction involvingN-methylmaleimide as 1,3-dipolarophile and the appropriate azomethine ylide. Thelatter 1,3-dipolar species were generated in situ via de-carboxylative condensation reaction of the particulara-amino acid with pyridine-annelated isatin in aqueousmethanol under reflux. The structures of these newspirooxindole cycloadducts are based on microanalytical,spectral (IR, HRMS, and NMR), and X-ray crystal data (14) (PDF) ChemInform Abstract: Synthesis of 6-Ethyl-1,2,9-trioxopyrrolo[3,2-f]quinoline-8-carboxylic Acid.. Available from: https://www.researchgate.net/publication/264273057_ChemInform_Abstract_Synthesis_of_6-Ethyl-129-trioxopyrrolo32-fquinoline-8-carboxylic_Acid

This study reports for the first time the use of oxidized and non-oxidized multi-walled carbon nanotubes (MWCNTs) of different geometrical dimensions for Hg(II) adsorption and preconcentration in water samples. The shapes of the Hg isotherms varied from L2, C1 and H2 according to the dimensions and oxidation conditions of the MWCNTs. Analysis of adsorption data by Langmuir, Freundlich and Dubinin–Radushkevich isotherms revealed that Hg(II) removal by L-MWCNT-4060-NA (nitric acid-oxidized MWCNT of external diameter 40–60 nm and length 5–15 μm) has the lowest sorption energy, which reflects the favorable uptake of Hg(II) by this adsorbent. Sorbents showed variable sorption capacities for mercury (0.70–3.83 mg g−1). However, in the preconcentration experiments, L-MWCNT-4060-NA exhibited the highest enrichment efficiency for a preconcentration of 100 μg L−1 Hg(II) at pH 7. The limit of quantifications of Hg(II) was 0.0123 μg L−1 in water. Analysis of Hg(II) in tap and reservoir waters gave high spike recovery (88–95%, RSD < 3%). Mineral water was used to check interference from foreign ions. The method was validated by determination of mercury in digested phosphate rock samples and certified reference Polish tobacco leaves, in which the method was highly accurate and precise.Research Highlights► Oxidation and dimensions of MWCNT affect Hg sorption. ► Various sorption models are applied. ► Solid phase extraction procedure of Hg(II) is optimized. ► The method is precise and accurate. ► Hg was determined in real waters, tobacco and phosphate rock.

This study reports for the first time the use of oxidized and non-oxidized multi-walled carbon nanotubes (MWCNTs) of different geometrical dimensions for Hg(II) adsorption and preconcentration in water samples. The shapes of the Hg isotherms varied from L2, C1 and H2 according to the dimensions and oxidation conditions of the MWCNTs. Analysis of adsorption data by Langmuir, Freundlich and Dubinin–Radushkevich isotherms revealed that Hg(II) removal by L-MWCNT-4060-NA (nitric acid-oxidized MWCNT of external diameter 40–60 nm and length 5–15 μm) has the lowest sorption energy, which reflects the favorable uptake of Hg(II) by this adsorbent. Sorbents showed variable sorption capacities for mercury (0.70–3.83 mg g−1). However, in the preconcentration experiments, L-MWCNT-4060-NA exhibited the highest enrichment efficiency for a preconcentration of 100 μg L−1 Hg(II) at pH 7. The limit of quantifications of Hg(II) was 0.0123 μg L−1 in water. Analysis of Hg(II) in tap and reservoir waters gave high spike recovery (88–95%, RSD < 3%). Mineral water was used to check interference from foreign ions. The method was validated by determination of mercury in digested phosphate rock samples and certified reference Polish tobacco leaves, in which the method was highly accurate and precise.Research Highlights► Oxidation and dimensions of MWCNT affect Hg sorption. ► Various sorption models are applied. ► Solid phase extraction procedure of Hg(II) is optimized. ► The method is precise and accurate. ► Hg was determined in real waters, tobacco and phosphate rock.

This study reports for the first time the use of oxidized and non-oxidized multi-walled carbon nanotubes (MWCNTs) of different geometrical dimensions for Hg(II) adsorption and preconcentration in water samples. The shapes of the Hg isotherms varied from L2, C1 and H2 according to the dimensions and oxidation conditions of the MWCNTs. Analysis of adsorption data by Langmuir, Freundlich and Dubinin–Radushkevich isotherms revealed that Hg(II) removal by L-MWCNT-4060-NA (nitric acid-oxidized MWCNT of external diameter 40–60 nm and length 5–15 μm) has the lowest sorption energy, which reflects the favorable uptake of Hg(II) by this adsorbent. Sorbents showed variable sorption capacities for mercury (0.70–3.83 mg g−1). However, in the preconcentration experiments, L-MWCNT-4060-NA exhibited the highest enrichment efficiency for a preconcentration of 100 μg L−1 Hg(II) at pH 7. The limit of quantifications of Hg(II) was 0.0123 μg L−1 in water. Analysis of Hg(II) in tap and reservoir waters gave high spike recovery (88–95%, RSDb3%). Mineral water was used to check interference from foreign ions. The method was validated by determination of mercury in digested phosphate rock samples and certified reference Polish tobacco leaves, in which the method was highly accurate and precise.

A facile synthesis of some methyl 5-(arylamino)-4-oxothieno[2,3-b]thiopyran-6-carboxylates 6a–g is achieved via direct reaction of deprotonated methyl 3-(2,5-dichlorothien-3-yl)-3-oxopropanoate with aryl iso-thiocyanates in anhydrous tetrahydrofuran (THF) under reflux. Upon saponification of 6a,b, the ester group is eliminated, most logically via decarboxylation of the presumably-formed carboxyl group. Structures of the new compounds 6a–g and 7a,b are supported by micro-analytical and spectral [NMR, MS electron impact (EI) and HRMS] data. (14) (PDF) Fused thia-heterocycles via isothiocyanates. Part II. A convenient synthesis of some new thieno[2,3-b]thiopyran-4-one derivatives. Available from: https://www.researchgate.net/publication/322670660_Fused_thia-heterocycles_via_isothiocyanates_Part_II_A_convenient_synthesis_of_some_new_thieno23-bthiopyran-4-one_derivatives [accessed Jun 04 2021].

A selected set of substituted pyridone-annelated isoindigos 3a–f has been synthesized via interaction of 5- and 6-substituted oxindoles 2a–f with 6-ethyl-1,2,9-trioxopyrrolo[3,2-f]quinoline-8-carboxylic acid (1) in acetic acid at reflux. Among these isoindigos, the 5'-chloro and 5'-bromo derivatives 3b and 3d show strong and selective antiproliferative activities against a panel of human hematological and solid tumor cell-lines, but not against noncancerous cells, suggesting their potential use as anticancer agents. In all the tested cell lines, compound 3b was a 25%–50% more potent inhibitor of cell growth than 3d, suggesting the critical role of the substitution at 5'-position of the benzo-ring E. The IC50 values after 48 hours incubation with the 5'-chloro compound 3b were 6.60 µM in K562, 8.21 µM in THP-1, 8.97 µM in HepG2, 11.94 µM in MCF-7 and 14.59 µM in Caco-2 cancer cells, while the IC50 values in noncancerous HEK-293 and L-929 were 30.65 µM and 40.40 µM, respectively. In addition, compound 3b induced higher levels apoptosis in K562 cells than 3d, as determined by annexin V/7-AAD flowcytometry analysis. Therefore, further characterization of the antitproliferative mechanisms of compounds 3b and 3d may provide a novel chemotherapeutic agents.

Treatment of 1,4-(SeSiMe3)2-C6H4 (1) with two equiv of ClC(O)R (2) (a, R = 2- c C4H3O; b, R = 2-cC4H3S; c, R = 3- c C4H3S) produced the corresponding phenylene carboselenolates 1,4-(SeC(O)R)2- C6H4 (3a–c), while the reaction of 1,4-(SLi)2-C6H4 (4) with ClC(O)R (2) in a 1:2 molar ratio gave phenylene carbothiolates 1,4-(SC(O)R)2-C6H4 (5a–c). Compounds 3a–c and 5a–c were characterized by elemental analysis, NMR (1H, 13C{1H}, 77Se{1H}) and IR spectroscopy. The molecular structures of 3a–c and 5a–c in the solid state were determined by single-crystal X-ray structure analysis. The carbochalcogenato groups and the heteroatoms of the 5-membered rings are in an anti-arrangement with respect to each other. Cyclic voltammetry measurements show irreversible reduction processes for the 5-membered heterocyclic redox moiety in which reduction of these compounds lead to decomposition of the original compounds to unidentified species and show redox potentials between 1480 and 1580 mV for 3a-c and 1470-1490 mV for 5a-c, relative to the FcH/FcH? redox couple. Also, thioester-functionalized systems 5a-c show significantly higher reduction potentials as compared to selenoesters 3a-c, reflecting the minor electron-donating effect of the sulfur atoms. The molecular electronic structures of the title compounds were additionally investigated by DFT calculations, revealing different degrees of HOMO-LUMO energy gaps within the series of 3a–c and 5a–c, due to a lowering in LUMO energy, depending on the nature of the heterocyclic ring. The calculations showed that the HOMO and LUMO are mainly located on the selenoester/thioester functionalized heterocyclic. The phase transition temperatures and enthalpies of the title compounds were detected by differential scanning calorimetry (DSC) analysis and the phases are confirmed by polarizing optical microscopy (POM). The mesomorphic investigation shows that compound 5a only exhibits enantiotropic smectic B (SmB) mesophase. In contrast, the other compounds do not show mesomorphic behavior, but simply changes from the solid crystalline state to the isotropic liquid. Biological activity of the compounds was evaluated using cytotoxicity assay on different cancer cell lines. Only compound 3c showed selective cytotoxic effect against MDA-231 and PC-3 cancer cell lines.

Schiff base diethyl 4,4-(pentane-2,4-diylidenebis(azanylylidene))benzoate (1) as a new ligand (L) was prepared by the reaction of acetylacetone with benzocaine in the ratio of 1 : 1. Two transition-metal complexes, [Ni(II)(LCl(HOEt))] (2) and [Zn(II)(LCl(HOEt))] (3), have been synthesized from metal salts with didentate Schiff base ligand (L) and characterized by elemental analyses, FT-IR, 1H NMR, 13C NMR UV-Vis spectroscopy, and magnetic susceptibility. +e biological activity of the complexes was studied. In addition, the M06-2x density function theory method and the 6-31G(d) basic set were applied to determine the optimized structures of 1–3 and to determine their IR and 1H NMR, 13C NMR spectra theoretically. +e data are in good agreement with the experimental results. +e geometries of complexes 2 and 3 were determined to be square-planar for 2 and tetrahedral for 3.

A series of novel pyridine-annelated spirooxindole-3,2′-pyrrolidines was prepared via 1,3-cycloaddition reaction involving N-methylmaleimide as 1,3-dipolarophile and the appropriate azomethine ylide. The latter 1,3-dipolar species were generated in situ via decarboxylative condensation reaction of the particular α-amino acid with pyridine-annelated isatin in aqueous methanol under reflux. The structures of these new spirooxindole cycloadducts are based on microanalytical, spectral (IR, HRMS, and NMR), and X-ray crystal data.

A series of novel pyridine-annelated spirooxindole-3,2′-pyrrolidines was prepared via 1,3-cycloaddition reaction involving N-methylmaleimide as 1,3-dipolarophile and the appropriate azomethine ylide. The latter 1,3-dipolar species were generated in situ via decarboxylative condensation reaction of the particular α-amino acid with pyridine-annelated isatin in aqueous methanol under reflux. The structures of these new spirooxindole cycloadducts are based on microanalytical, spectral (IR, HRMS, and NMR), and X-ray crystal data.

A series of novel pyridine-annelated spirooxindole-3,20 -pyrrolidines was prepared via 1,3-cycloaddition reaction involving N-methylmaleimide as 1,3- dipolarophile and the appropriate azomethine ylide. The latter 1,3-dipolar species were generated in situ via decarboxylative condensation reaction of the particular aamino acid with pyridine-annelated isatin in aqueous methanol under reflux. The structures of these new spirooxindole cycloadducts are based on microanalytical, spectral (IR, HRMS, and NMR), and X-ray crystal data

Aseriesofnovelpyridine-annelatedspirooxindole-3,20-pyrrolidines was prepared via 1,3-cy-cloaddition reaction involvingN-methylmaleimide as 1,3-dipolarophile and the appropriate azomethine ylide. Thelatter 1,3-dipolar species were generated in situ via de-carboxylative condensation reaction of the particulara-amino acid with pyridine-annelated isatin in aqueousmethanol under reflux. The structures of these newspirooxindole cycloadducts are based on microanalytical,spectral (IR, HRMS, and NMR), and X-ray crystal data (14) (PDF) ChemInform Abstract: Synthesis of 6-Ethyl-1,2,9-trioxopyrrolo[3,2-f]quinoline-8-carboxylic Acid.. Available from: https://www.researchgate.net/publication/264273057_ChemInform_Abstract_Synthesis_of_6-Ethyl-129-trioxopyrrolo32-fquinoline-8-carboxylic_Acid

This study reports for the first time the use of oxidized and non-oxidized multi-walled carbon nanotubes (MWCNTs) of different geometrical dimensions for Hg(II) adsorption and preconcentration in water samples. The shapes of the Hg isotherms varied from L2, C1 and H2 according to the dimensions and oxidation conditions of the MWCNTs. Analysis of adsorption data by Langmuir, Freundlich and Dubinin–Radushkevich isotherms revealed that Hg(II) removal by L-MWCNT-4060-NA (nitric acid-oxidized MWCNT of external diameter 40–60 nm and length 5–15 μm) has the lowest sorption energy, which reflects the favorable uptake of Hg(II) by this adsorbent. Sorbents showed variable sorption capacities for mercury (0.70–3.83 mg g−1). However, in the preconcentration experiments, L-MWCNT-4060-NA exhibited the highest enrichment efficiency for a preconcentration of 100 μg L−1 Hg(II) at pH 7. The limit of quantifications of Hg(II) was 0.0123 μg L−1 in water. Analysis of Hg(II) in tap and reservoir waters gave high spike recovery (88–95%, RSD < 3%). Mineral water was used to check interference from foreign ions. The method was validated by determination of mercury in digested phosphate rock samples and certified reference Polish tobacco leaves, in which the method was highly accurate and precise.Research Highlights► Oxidation and dimensions of MWCNT affect Hg sorption. ► Various sorption models are applied. ► Solid phase extraction procedure of Hg(II) is optimized. ► The method is precise and accurate. ► Hg was determined in real waters, tobacco and phosphate rock.

This study reports for the first time the use of oxidized and non-oxidized multi-walled carbon nanotubes (MWCNTs) of different geometrical dimensions for Hg(II) adsorption and preconcentration in water samples. The shapes of the Hg isotherms varied from L2, C1 and H2 according to the dimensions and oxidation conditions of the MWCNTs. Analysis of adsorption data by Langmuir, Freundlich and Dubinin–Radushkevich isotherms revealed that Hg(II) removal by L-MWCNT-4060-NA (nitric acid-oxidized MWCNT of external diameter 40–60 nm and length 5–15 μm) has the lowest sorption energy, which reflects the favorable uptake of Hg(II) by this adsorbent. Sorbents showed variable sorption capacities for mercury (0.70–3.83 mg g−1). However, in the preconcentration experiments, L-MWCNT-4060-NA exhibited the highest enrichment efficiency for a preconcentration of 100 μg L−1 Hg(II) at pH 7. The limit of quantifications of Hg(II) was 0.0123 μg L−1 in water. Analysis of Hg(II) in tap and reservoir waters gave high spike recovery (88–95%, RSD < 3%). Mineral water was used to check interference from foreign ions. The method was validated by determination of mercury in digested phosphate rock samples and certified reference Polish tobacco leaves, in which the method was highly accurate and precise.Research Highlights► Oxidation and dimensions of MWCNT affect Hg sorption. ► Various sorption models are applied. ► Solid phase extraction procedure of Hg(II) is optimized. ► The method is precise and accurate. ► Hg was determined in real waters, tobacco and phosphate rock.

This study reports for the first time the use of oxidized and non-oxidized multi-walled carbon nanotubes (MWCNTs) of different geometrical dimensions for Hg(II) adsorption and preconcentration in water samples. The shapes of the Hg isotherms varied from L2, C1 and H2 according to the dimensions and oxidation conditions of the MWCNTs. Analysis of adsorption data by Langmuir, Freundlich and Dubinin–Radushkevich isotherms revealed that Hg(II) removal by L-MWCNT-4060-NA (nitric acid-oxidized MWCNT of external diameter 40–60 nm and length 5–15 μm) has the lowest sorption energy, which reflects the favorable uptake of Hg(II) by this adsorbent. Sorbents showed variable sorption capacities for mercury (0.70–3.83 mg g−1). However, in the preconcentration experiments, L-MWCNT-4060-NA exhibited the highest enrichment efficiency for a preconcentration of 100 μg L−1 Hg(II) at pH 7. The limit of quantifications of Hg(II) was 0.0123 μg L−1 in water. Analysis of Hg(II) in tap and reservoir waters gave high spike recovery (88–95%, RSDb3%). Mineral water was used to check interference from foreign ions. The method was validated by determination of mercury in digested phosphate rock samples and certified reference Polish tobacco leaves, in which the method was highly accurate and precise.

A facile synthesis of some methyl 5-(arylamino)-4-oxothieno[2,3-b]thiopyran-6-carboxylates 6a–g is achieved via direct reaction of deprotonated methyl 3-(2,5-dichlorothien-3-yl)-3-oxopropanoate with aryl iso-thiocyanates in anhydrous tetrahydrofuran (THF) under reflux. Upon saponification of 6a,b, the ester group is eliminated, most logically via decarboxylation of the presumably-formed carboxyl group. Structures of the new compounds 6a–g and 7a,b are supported by micro-analytical and spectral [NMR, MS electron impact (EI) and HRMS] data. (14) (PDF) Fused thia-heterocycles via isothiocyanates. Part II. A convenient synthesis of some new thieno[2,3-b]thiopyran-4-one derivatives. Available from: https://www.researchgate.net/publication/322670660_Fused_thia-heterocycles_via_isothiocyanates_Part_II_A_convenient_synthesis_of_some_new_thieno23-bthiopyran-4-one_derivatives [accessed Jun 04 2021].

A selected set of substituted pyridone-annelated isoindigos 3a–f has been synthesized via interaction of 5- and 6-substituted oxindoles 2a–f with 6-ethyl-1,2,9-trioxopyrrolo[3,2-f]quinoline-8-carboxylic acid (1) in acetic acid at reflux. Among these isoindigos, the 5'-chloro and 5'-bromo derivatives 3b and 3d show strong and selective antiproliferative activities against a panel of human hematological and solid tumor cell-lines, but not against noncancerous cells, suggesting their potential use as anticancer agents. In all the tested cell lines, compound 3b was a 25%–50% more potent inhibitor of cell growth than 3d, suggesting the critical role of the substitution at 5'-position of the benzo-ring E. The IC50 values after 48 hours incubation with the 5'-chloro compound 3b were 6.60 µM in K562, 8.21 µM in THP-1, 8.97 µM in HepG2, 11.94 µM in MCF-7 and 14.59 µM in Caco-2 cancer cells, while the IC50 values in noncancerous HEK-293 and L-929 were 30.65 µM and 40.40 µM, respectively. In addition, compound 3b induced higher levels apoptosis in K562 cells than 3d, as determined by annexin V/7-AAD flowcytometry analysis. Therefore, further characterization of the antitproliferative mechanisms of compounds 3b and 3d may provide a novel chemotherapeutic agents.

Treatment of 1,4-(SeSiMe3)2-C6H4 (1) with two equiv of ClC(O)R (2) (a, R = 2- c C4H3O; b, R = 2-cC4H3S; c, R = 3- c C4H3S) produced the corresponding phenylene carboselenolates 1,4-(SeC(O)R)2- C6H4 (3a–c), while the reaction of 1,4-(SLi)2-C6H4 (4) with ClC(O)R (2) in a 1:2 molar ratio gave phenylene carbothiolates 1,4-(SC(O)R)2-C6H4 (5a–c). Compounds 3a–c and 5a–c were characterized by elemental analysis, NMR (1H, 13C{1H}, 77Se{1H}) and IR spectroscopy. The molecular structures of 3a–c and 5a–c in the solid state were determined by single-crystal X-ray structure analysis. The carbochalcogenato groups and the heteroatoms of the 5-membered rings are in an anti-arrangement with respect to each other. Cyclic voltammetry measurements show irreversible reduction processes for the 5-membered heterocyclic redox moiety in which reduction of these compounds lead to decomposition of the original compounds to unidentified species and show redox potentials between 1480 and 1580 mV for 3a-c and 1470-1490 mV for 5a-c, relative to the FcH/FcH? redox couple. Also, thioester-functionalized systems 5a-c show significantly higher reduction potentials as compared to selenoesters 3a-c, reflecting the minor electron-donating effect of the sulfur atoms. The molecular electronic structures of the title compounds were additionally investigated by DFT calculations, revealing different degrees of HOMO-LUMO energy gaps within the series of 3a–c and 5a–c, due to a lowering in LUMO energy, depending on the nature of the heterocyclic ring. The calculations showed that the HOMO and LUMO are mainly located on the selenoester/thioester functionalized heterocyclic. The phase transition temperatures and enthalpies of the title compounds were detected by differential scanning calorimetry (DSC) analysis and the phases are confirmed by polarizing optical microscopy (POM). The mesomorphic investigation shows that compound 5a only exhibits enantiotropic smectic B (SmB) mesophase. In contrast, the other compounds do not show mesomorphic behavior, but simply changes from the solid crystalline state to the isotropic liquid. Biological activity of the compounds was evaluated using cytotoxicity assay on different cancer cell lines. Only compound 3c showed selective cytotoxic effect against MDA-231 and PC-3 cancer cell lines.

Schiff base diethyl 4,4-(pentane-2,4-diylidenebis(azanylylidene))benzoate (1) as a new ligand (L) was prepared by the reaction of acetylacetone with benzocaine in the ratio of 1 : 1. Two transition-metal complexes, [Ni(II)(LCl(HOEt))] (2) and [Zn(II)(LCl(HOEt))] (3), have been synthesized from metal salts with didentate Schiff base ligand (L) and characterized by elemental analyses, FT-IR, 1H NMR, 13C NMR UV-Vis spectroscopy, and magnetic susceptibility. +e biological activity of the complexes was studied. In addition, the M06-2x density function theory method and the 6-31G(d) basic set were applied to determine the optimized structures of 1–3 and to determine their IR and 1H NMR, 13C NMR spectra theoretically. +e data are in good agreement with the experimental results. +e geometries of complexes 2 and 3 were determined to be square-planar for 2 and tetrahedral for 3.