Silver-catalyzed C2-selective direct alkylation of heteroarenes with tertiary cycloalkanols.

A silver-catalyzed regioselective C2-alkylation of heteroarenes with tertiary cycloalkanols under radical conditions was developed. This tandem process, which includes selective C-H activation, C(sp3)-C(sp3) bond cleavage, and C(sp3)-C(sp2) bond formation, affords a novel and environmentally friendly approach for the production of carbonyl-containing alkyl-substituted heteroarenes with moderate to good yields.

Synthesis, crystal structure, optical properties and antibacterial evaluation of novel imidazo[1, 5-a]pyridine derivatives bearing a hydrazone moiety.

A series of novel imidazo[1,5-a]pyridine-hydrazone derivatives were synthesized and characterized by infrared spectroscopy (IR), 1H NMR, 13C NMR and high resolution mass spectrometer (HRMS). Typically, the spatial structure of compound 3j was determined using X-ray diffraction analysis. The UV-vis absorption and fluorescence spectral characteristics of the compounds in dichloromethane and acetonitrile were investigated. Absorption peaks could be observed in the wavelength range 290-450 nm. It can also be seen that they display very similar maximum emission. The group attached to hydrazone hardly influenced the maximum emission. Furthermore, all the compounds were evaluated for antibacterial activity and were found to be more effective against Staphylococcus aureus, Listeria monocytogenes, Escherichia coli, Salmonella typhimurium, Pseudomonas aeruginosa and Shigella compared with chloramphenicol.

Synthesis, characterization, optical properties and theoretical studies of novel substituted imidazo[1,5-a]pyridinyl 1,3,4-oxadiazole derivatives.

Novel imidazo[1,5-a]pyridinyl 1,3,4-Oxadiazole derivatives were synthesized and characterised by IR, (1)H NMR and HRMS.UV-vis absorption and fluorescence properties of these compounds in different solutions showed that the maximal emission wavelength was not significantly changed in different solvents; however, maximum absorption wavelength was blue-shifted with the increase of solvent polarity. Absorption λ(max) and emission λ(max) was less correlated with substituent groups on benzene rings. The calculated molecular orbital correlates well with their absorption.

3-(4-Bromo-phen-yl)-1-(4-chloro-benz-yl)-1H-pyrazole-5-carbaldehyde.

The title compound, C(17)H(12)BrClN(2)O, was synthesized by oxidation of [3-(4-bromo-phen-yl)-1-(4-chloro-benz-yl)-1H-pyrazol-5-yl]methanol under mild conditions. The pyrazole ring makes dihedral angles of 3.29 (9) and 74.91 (4)°, respectively, with the bromo-phenyl and chloro-phenyl rings.

Ethyl 1-(4-chloro-benz-yl)-3-phenyl-1H-pyrazole-5-carboxyl-ate.

In the title compound, C(19)H(17)ClN(2)O(2), the pyrazole ring makes dihedral angles of 6.97 (5) and 79.25 (1)°, respectively, with the phenyl and chlorophenyl rings, respectively. In the crystal, C-H⋯O hydrogen bonds are observed.

Ethyl 4-acetamido-3-acet-oxy-2-benzyl-3-methyl-butano-ate.

The crystal structure of the title compound, C(18)H(25)NO(5), is stabilized by inter-molecular N-H⋯O hydrogen bonds, which form inversion dimers. The ethyl group is disordered over two positions in a 0.651 (12):0.349 (12) ratio.

Ethyl 8-(4-nitro-phen-yl)imidazo[1,2-a]pyridine-7-carboxyl-ate.

In the title compound, C(16)H(13)N(3)O(4), the imidazo[1,2-a]pyridine and benzene rings make a dihedral angle of 56.21 (2)°. The crystal packing is stabilized by weak π-π stacking inter-actions [centroid-centroid distances = 3.787 (2) Å] and C-H⋯O inter-molecular hydrogen-bonding inter-actions.

2-Cyclo-hexyl-4-[(3,5-dimethyl-piperidin-1-yl)meth-yl]-5-methyl-phenol.

The title compound, C(21)H(33)NO, crystallizes with three independent mol-ecules in the asymmetric unit. The cyclo-hexane and piperidine rings adopt chair conformations. The crystal packing is stabilized by inter-molecular O-H⋯N and C-H⋯O hydrogen bonds, and by weak π-π stacking inter-actions [centroid-centroid distance = 3.876 (2) Å].

2-(2-Methyl-5-nitro-1H-imidazol-1-yl)ethyl N-methyl-carbamate.

In the title compound, C(8)H(12)N(4)O(4), the essentially planar methyl-carbamoyloxymethyl group [maximum deviation 0.038 (3) Å] and the imidazole ring make a dihedral angle of 48.47 (3)°. The crystal packing is stabilized by inter-molecular N-H⋯N and C-H⋯O hydrogen bonds, which link the mol-ecules into infinite ribbons running along the a axis, and by weak π-π stacking inter-actions [centroid-centroid distance = 3.894 (2) Å].

11H-Dibenzo[b,e]azepine-6-carbonitrile.

The title compound, C(15)H(10)N(2), crystallizes with two independent mol-ecules in the asymmetric unit. The two benzene rings make dihedral angles of 60.32 (2) and 61.35 (3)°. The crystal packing is stabilized by weak π-π stacking inter-actions [centroid-to-centroid distances = 3.673 (4) and 3.793 (4) Å].

The synthesis, characterization and optical properties of novel 5-(3-aryl-1H-pyrazol-5-yl)-2-(3-butyl-1-chloroimidazo[1,5-a]pyridin-7-yl)-1,3,4-oxadiazole.

A series of novel 5-(3-aryl-1H-pyrazol-5-yl)-2-(3-butyl-1-chloroimidazo[1,5-a]- pyridin-7-yl)-1,3,4-oxadiazole derivatives has been synthesized from 3-butyl-1-chloroimidazo[1,5-a]pyridine-7-carboxylic acid and ethyl 3-aryl-1H-pyrazole-5-carboxylate. The compounds were characterized using IR, (1)H NMR, HRMS and UV-vis absorption. The fluorescence spectral characteristics of the compounds in dichloromethane were investigated. The results showed that absorption λmax and emission λmax was less correlated with substituent groups on N-1 position of pyrazole moiety and para position of benzene moiety. The calculated molecular orbital correlates well with their absorption.