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High Temperature Bromination. Part 12: Bromination of 7-Oxabenzonorbornadiene: Synthesis of 2,3-Dibromo-7-oxabenzonorbornadiene

Abstract The electrophilic addition of bromine to 7-oxabenzonorbornadiene ( 8 ) at 0°C led in high yield to the formation of dibromoaldehyde 10 . However, high-temperature bromination of 8 in carbon tetrachloride at 77°C gave non-rearranged products 17 and 18 . From the elimination of non-rearranged products, 2-bromo-7-oxabenzonorbornadiene ( 12 ) was obtained. Similarly, bromination of monobromide 12 at 77°C yielded the non-rearranged tribromides 19 and 20 while bromination of 12 at 0°C gave the rearranged product 11 . The dehydrobromination of tribromides ( 19 , 20 ) provided the 2,3-dibromo-7-oxabenzonorbornadiene ( 21 ), which is a synthon for the trimerization, in high yield

Synthesis and biological activity of new cycloalkylthiophene-Schiff bases and their Cr(III) and Zn(II) complexes

A series of some novel Ethyl 2-((1-hydroxynaphthalen-2-yl)methyleneamino)-5,6-dihydro-4H-cyclopenta[b]thiopehene-3-carboxylate, Ethyl 2-((1-hydroxynaphthalen-2-yl)methyleneamino)-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carboxylate, Ethyl 2-((1-hydroxynaphtalen-2-yl)methyleneamino)-5,6,7,8-tetrahydro-4H-cyclohepta[b]thiophene-3-carboxylate and their Cr(III) and Zn(II) complexes have been synthesized. All of these substances have been examined for antibacterial activity against pathogenic strains Listeria monocytogenes 4b (ATCC-19115), Staphylococcus aureus (ATCC25923), Proteus OX2 Wrah (ETS.40-A-4), Escherichia coli (ATCC-1280), Salmonella typhi H (NCTC-901.8394), Pseudomonas putida sp., Brucella abortus (A.99, UK-1995) RSKK-03026. Sh. boydii type 11 (Pasteur51.6), Sh. boydii type 16 (cHe 67.11), Sh. boydii type 6 (RSKK-96043), and antifungal activity against Candida albicans (Y-1200-NIH, Tokyo). Some of the compounds exhibited activity comparable to ampicillin ofloxacin, nystatin, kanamycin, sulphamethoxazol, amoxycillin, and chloroamphenicol. Most of the studied compounds were found effective against bacteria studied and yeast.

Synthesis and evaluation of a series of aminocyanopyridines as antimicrobial agents

With the aim of developing potential antimicrobials, a series of 2-amino-3-cyanopyridines incorporating both sulfur and oxygen as part of the heteroaromatic ring (methyl thiophene, methyl furan) and fused cycloalkane groups were synthesized and characterized by FTIR, 1H-NMR, 13C-NMR, and bases of elemental analysis. All synthesized compounds were evaluated for their in vitro antibacterial and antifungal activity. Antibacterial and antifungal activities of aminocyanopyridines against Pseudomonas aeruginosa ATCC 29212, Bacillus subtilis RSKK 244, Bacillus megaterium (clinical isolate), the gram-positive bacterium Micrococcus luteus NRRLB 4375, and the fungus Candida albicans ATCC 90028 were studied. The relationship between the functional-group variation and the biological activity of the evaluated compounds is discussed.

A new, safe and convenient procedure for reduction of naphthalene and anthracene: synthesis of tetralin in a one-pot reaction

Reduction of naphthalene and anthracene with sodium and tert-butyl alcohol gave 1,4-dihydronaphthalene and 9,10-dihydroanthracene respectively in high yields at room temperature (r.t.) as the sole products. The synthesis of tetralin from naphthalene was carried out in a one-pot reaction via 1,4-dihydronaphthalene. The reduced products were easily isolated.

Synthesis of 2‐amino‐3‐cyanopyridine derivatives and investigation of their carbonic anhydrase inhibition effects

The conversion of carbon dioxide (CO2) and bicarbonate (HCO3−) to each other is very important for living metabolism. Carbonic anhydrase (CA, E.C.4.2.1.1), a metalloenzyme familly, catalyzes the interconversion of these ions (CO2 and HCO3−) and are very common in living organisms. In this study, a series of novel 2‐amino‐3‐cyanopyridines supported with some functional groups was synthesized and tested as potential inhibition effects against both cytosolic human CA I and II isoenzymes (hCA I and II) using by Sepharose‐4B‐l‐tyrosine‐sulfanilamide affinity chromatography. The structural elucidations of novel 2‐amino‐3‐cyanopyridines were achieved by NMR, IR, and elemental analyses. Ki values of the novel synthesized compounds were found in range of 2.84–112.44 μM against hCA I and 2.56–31.17 μM against hCA II isoenzyme. While compound 7d showed the best inhibition activity against hCA I (Ki: 2.84 μM), the compound 7b demonstrated the best inhibition profile against hCA II isoenzyme (Ki: 2.56 μM).

Ni(II)-tetrahedral complexes: characterization, antimicrobial properties, theoretical studies and a new family of charge-transfer transitions.

A new amine containing selenium and their five imine, (SeSchX)(X: -H, F, Cl, Br, CH3), and Ni (II) complexes, [Ni(SeSchX)(H2O)2]Cl/[Ni(SeSchCl)(H2O)Cl], were synthesized. The compounds were characterized by means of elemental analyses, (13)C and (1)H NMR (for imine), FT-IR, UV-Visible spectroscopy, TGA/DTA and elemental analyses. [Ni(SeSchCl)(H2O)Cl] complex from Ni(II) complexes changes color from yellow to orange in the range pH 5-7. [Ni(SeSchCl)(H2O)Cl] complex has ligand-to-metal charge-transfer (LMCT) transitions in the basic medium. Excitation characteristics and energetic of [Ni(SeSchCl)(H2O)Cl] complex, examined via TD-DFT calculations, reveals transitions of LMCT and π→π(*) character that matches the experimental values. [Ni(SeSchCl)(H2O)Cl] complex showed the highest antibacterial activity when compared to other complexes reported in this work.

Unusual photorearrangement of 1,7-disubstituted 7-azabenzonorbornadiene

Abstract1-(11-Benzoyl-11-azatricyclo[6.2.1.02,7]undeca-2,4,6,9-tetraen-1-yl)ethanone was synthesized by cycloaddition of 2-acetyl-N-benzoylpyrrole to benzyne. Direct photolysis of 1-(11-benzoyl-11-azatricyclo-[6.2.1.02,7]undeca-2,4,6,9-tetraen-1-yl)ethanone in benzene gave N-(4-acetylnaphthalen-1-yl)benzamide. The formation of this product is discussed in terms of radical-stabilizing and destabilizing effect of electron-withdrawing group in the formation of cyclopropane ring.

Syntheses of and photochemical studies of 2,3-disubstituted 1,4-epoxy-1,4-dihydronaphthalenes

A method for synthesis of 3-methyl-1,4-epoxy-1,4-dihydronaphthalene-2-carboxylic acid and 3-methyl-1,4-epoxy-1,4-dihydronaphthalene-2-carbonitrile was developed starting from 1,4-epoxy-1,4-dihydronaphthalene; direct photolysis of 3-methyl-1,4-epoxy-1,4-dihydronaphthalene-2-carbonitrile and methyl 3-methyl-1,4-epoxy-1,4-dihydronaphthalene-2-carboxylate in benzene gave indene derivatives.

Green synthesis of γ-Fe 2 O 3 nanoparticles for methane gas sensing

Green synthesis is becoming increasingly important as an eco-friendly alternative to the traditional production process because of its growing industrial applications. In this study, peroxidase enzymes of the leaf extracts of the plants Ficus carica (Fig) and Euphorbia amygdaloides (Euphorbia) were used for the synthesis of γ-Fe2O3 nanoparticles (NPs). The structural, morphological and methane gas sensing properties of γ-Fe2O3 NPs were investigated. γ-Fe2O3 NPs obtained from the Fig plant peroxidase enzyme showed a higher response, selectivity and short response/recovery time than γ-Fe2O3 NPs obtained from the Euphorbia plant peroxidase enzyme, which exhibited 15% response to 1-ppm methane gas at 150 °C. Impedance spectroscopy analysis showed that the resistance due to the grain boundaries significantly contributed to the characteristics of gas sensing. It can be seen from results that γ-Fe2O3 NPs produced from peroxidase enzymes that purified from Fig plant have great potential for industrial applications.