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Well-organized zirconia (ZrO

The aim of this work is to study the influence of the nature and position of substitution at allyl benzene on the regioselectivity of the hydrosilylation reaction. We studied hydrosilylation of the various allyl derivatives with cyclic siloxane, D4H, and linears hydrosilylating agents, 1,1,3,3-tetramethyldisiloxane and MDHM, in the presence of platinum-based catalysts (Karstedt catalyst, platinum black). We also show the effects of the amount of catalyst on the conversion. Moreover, the influence on the temperature on catalytic activity and selectivity of the hydrosilylation reaction was explained. All new compounds were characterized by 1H, 13C, 29Si NMR and HRMS as well.

The ten-membered ring in the title molecule, C25H29ClN2O7, adopts an approximate chair–chair conformation, whereas the five-membered furan and pyrazole rings display envelope conformations. The mean plane of the furan ring is almost perpendicular to that of the pyrazole ring, as indicated by the dihedral angle between them of 86.45 (9)°. The pyrazole ring is slightly inclined to the plane of the attached phenyl ring, subtending a dihedral angle of 16.88 (8)°. The conformation of the molecule is stabilized by six intramolecular hydrogen bonds and crystal cohesion is ensured by five C—H...O hydrogen bonds, in addition to C—H...π interactions.

The ten-membered ring in the title mol-ecule, C

A series of novel spiropyrazoles and spiroisoxazolines was efficiently synthesized. Structural modifications were performed at the C-9 and C-13 positions of 9α- and 9β-hydroxyparthenolide, which were isolated from the aerial parts of Anvillea radiata. The structures and stereochemistry of the cycloadducts were fully established by spectroscopic methods including X-ray diffraction data.

The treatment of alkylated nitro derivatives of indazole with stannous chloride in alkanethiol gave after coupling of the obtained amines with 4-methoxybenzenesulfonyl chloride in pyridine the new N-(4-alkylsulfanylindazol-7-yl)-4-methoxybenzene sulfonamides via the nucleophilic substitution of hydrogen in position 4 of indazole, together with the expected 4-methoxy-N-(indazol-7-yl)-benzenesulfonamides. All the newly synthesized compounds have been characterized by elemental analysis and spectroscopic data.

Some new N-[6-indazolyl]arylsulfonamides and N-[alkoxy-6-indazolyl]arylsulfonamides were prepared by the reduction of 2-alkyl-6-nitroindazoles with SnCl2 in different alcohols, followed by coupling the corresponding amine with arylsulfonyl chlorides in pyridine. The newly synthesized compounds were evaluated for their antiproliferative and apoptotic activities against two human tumor cell lines: A2780 (ovarian carcinoma) and A549 (lung adenocarcinoma). Preliminary in vitro pharmacological studies revealed that N-(2-allyl-2H-indazol-6-yl)-4-methoxybenzenesulfonamide 4 and N-[7-ethoxy-2-(4-methyl-benzyl)-2H-indazol-6-yl]-4-methyl-benzenesulfonamide 9 exhibited significant antiproliferative activity against the A2780 and A549 cell lines with IC50 values in the range from 4.21 to 18.6 µM, and also that they trigger apoptosis in a dose-dependent manner. Furthermore, both active compounds were able to cause an arrest of cells in the G2/M phase of the cell cycle, typical but not exclusive of tubulin interacting agents, although only infrequent interactions with the microtubule network were observed by immunofluorescence microscopy, while docking analysis showed a possible different behavior between the two active compounds.

2-Vinyl-5,10,15,20-tetraphenylporphyrinatozinc(II) reacts with nitrile imines, generated in situ from ethyl hydrazono-α-bromoglyoxylates, affording the corresponding pyrazolines in good to excellent yields. Treatment of pyrazoline derivatives with DDQ affords the corresponding pyrazole derivatives with moderate to excellent yields. When the hydrolysis of ester group in the pyrazoline derivatives was considered, it was observed the concomitant oxidation of the heterocyclic unit, which allowed directly obtaining porphyrin-pyrazole derivatives with a carboxylic group, in very good yields. The photophysical properties of the pyrazoline and pyrazole porphyrin derivatives show that the influence of the heterocyclic substituents is limited by the tendency of these molecules to aggregate. All other properties and especially the triplet kinetics remain unaffected. The adducts with low tendency to aggregate showed very high singlet oxygen yield, which makes these compounds interesting for their use as photosensitizers for PDT.

The synthesis of new 7-alkoxy-4-amino-protected indazole and 4-amino-protected indazole derivatives by the reduction of the nitro group of 4-nitroindazoles using anhydrous stannous chloride in different alcohols is described.

N-Aryl-C-ethoxycarbonylnitrile imines react with meso-tetrakis(pentafluorophenyl)porphyrin in 1,3-dipolar cycloadditions to yield novel pyrazolochlorins in moderate yields. The nitrile imines were generated in situ by base-induced dehydrobromination of ethyl hydrazono-αbromoglyoxylates. A number of different experimental conditions were considered for these cycloadditions, namely different bases, solvents and temperature; the best results were obtained using potassium carbonate in refluxing toluene. The photophysical properties of the new chlorins were investigated and the results suggest that two of them have potential for use in photodynamic therapy.

New N-(1H-7-indazolyl)-pyridinones have been prepared by the condensation of 2-pyrone derivatives with 7-aminoindazole in the presence of acid medium. They have been characterized by means of 1H and 13C NMR, IR, and mass spectroscopy. The structure of the compounds and the mechanism of their formation are reported.

Some new N-[6-indazolyl]arylsulfonamides and N-[alkoxy-6-indazolyl]arylsulfonamides were prepared by the reduction of 2-alkyl-6-nitroindazoles with SnCl2 in different alcohols, followed by coupling the corresponding amine with arylsulfonyl chlorides in pyridine. The newly synthesized compounds were evaluated for their antiproliferative and apoptotic activities against two human tumor cell lines: A2780 (ovarian carcinoma) and A549 (lung adenocarcinoma). Preliminary in vitro pharmacological studies revealed that N-(2-allyl-2H-indazol-6-yl)-4-methoxybenzenesulfonamide 4 and N-[7-ethoxy-2-(4-methyl-benzyl)-2H-indazol-6-yl]-4-methyl-benzenesulfonamide 9 exhibited significant antiproliferative activity against the A2780 and A549 cell lines with IC50 values in the range from 4.21 to 18.6 µM, and also that they trigger apoptosis in a dose-dependent manner. Furthermore, both active compounds were able to cause an arrest of cells in the G2/M phase of the cell cycle, typical but not exclusive of tubulin interacting agents, although only infrequent interactions with the microtubule network were observed by immunofluorescence microscopy, while docking analysis showed a possible different behavior between the two active compounds.

Recently, it has been reported that compounds bearing a sulfonamide moiety possess many types of biological activities, including anticancer activity. The present work reports the synthesis and antiproliferative evaluation of some N-(6(4)-indazolyl)benzenesulfonamides and 7-ethoxy-N-(6(4)-indazolyl)benzenesulfonamides. All compounds were evaluated for their in vitro antiproliferative activity against three tumor cell lines: A2780 (human ovarian carcinoma) A549 (human lung adenocarcinoma) and P388 (murine leukemia). The results indicated that sulfonamides 2c, 3c, 6d, 8, 13, 3b and 16 were endowed with a pharmacologically interesting antiproliferative activity with compounds 2c and 3c showing the lower IC(50) (from 0.50 ± 0.09 to 1.83 ± 0.52 μM and from 0.58 ± 0.17 to 5.83 ± 1.83 μM, respectively). Moreover, these indazoles were able to trigger apoptosis through the upregulation of the typical apoptosis markers p53 and bax. As regard to the hypothetic targets of these compounds, a preliminary docking analysis showed that all compounds seemed to interact with β-tubulin, in particular compound 3b that showed the lower Ki. The cytofluorimetric analysis of the cell cycle phases indicates that all compounds, when administered at their IC(75), caused a block in the G2/M phase of the cell cycle with the generation of subpopulations of cells with a number of chromosome >4n. When the IC(50)s were applied we observed a prevalent block in the G0/G1 phase except for compounds 16 and 8 where a partial G2/M block was present with a concomitant decrease of cells in the G0/G1 and S phases of the cell cycle. Altogether these results suggest a possible, but not exclusive, interaction with microtubules.

In the title compound, C(21)H(19)NO(7)S(2), the dihedral angles between the formyl-phenyl ring and the two meth-oxy-phenyl rings are 33.87 (9) and 41.00 (10)°. The S atoms have a distorted tetra-hedral geometry and the N atom shows a trigonally planar [r.m.s. deviation = 0.0437 (13) Å] coordination. The crystal structure is stabilized by inter-molecular C-H⋯O hydrogen bonds.

7-Alkoxy-4-amino-protected indazole and 4-amino-protected indazole derivatives are obtained by reduction of the nitro group in 4-nitroindazoles using anhydrous stannous chloride in different alcohols.

The position of the nitro group in indazoles and their structure have influence on their reaction behavior.

New N-(1H-7-indazolyl)-pyridinones have been prepared by the condensation of 2-pyrone derivatives with 7-aminoindazole in the presence of acid medium. They have been characterized by means of 1H and 13C NMR, IR, and mass spectroscopy. The structure of the compounds and the mechanism of their formation are reported.

In the title compound, C21H19NO7S2, the dihedral angles between the formylphenyl ring and the two methoxyphenyl rings are 33.87 (9) and 41.00 (10)°. The S atoms have a distorted tetrahedral geometry and the N atom shows a trigonally planar [r.m.s. deviation = 0.0437 (13) Å] coordination. The crystal structure is stabilized by intermolecular C—H...O hydrogen bonds.

In the title compound, C19H21N3O3S, the C—SO2—NH—C torsion angle is 66.20 (9)°. The dihedral angle between the benzene ring and the essentially planar indazole ring system [r.m.s. deviation = 0.0361 (1) Å] is 72.97 (6)°. The S atom has a distorted tetrahedral geometry [maximum deviation = O—S—O = 119.30 (6)°]. The crystal structure features inversion-related dimers linked by pairs of N—H...O hydrogen bonds. In addition, weak C—H...O interactions may stabilize the crystal packing.

New pyrazolo[1,5,4-ef][1,5]benzodiazepines have been synthesized by condensation of 7-aminoindazole with β-keto esters, alkylation and 1,3-dipolar cycloaddition. The peri- and regioselective cycloaddition of allylpyrazolo-1,5-benzodiazepinones and 2,4,6-trimethylbenzonitrile oxide was investigated by one-and two- dimensional 1 H and 1 3 C NMR spectrum.