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This effort focuses on the construction of novel pyrazolo[1,5‐a]pyrimidines bearing indole nucleus via the reaction of 3‐(1H‐indol‐3‐yl)‐1H‐pyrazol‐5‐amine (3) with the appropriate reagents or through solvent free condensations with active methylene components and triethyl orthoformate. The utility of (3) for the preparation of pyrazolo[5,1‐c][1, 2, 4]triazines was also explored via coupling of diazonium salt of (3) with active methylene compounds. Antioxidant activity screening of the synthetic targets showed that compounds (13), (14), (16), and (17) exhibited a promising activity. [ABSTRACT FROM AUTHOR]

Heteroleptic polypyridyl Ru complexes MMR-1 and MMR-2 containing 2-(methylthio)thienyl and 2-(4-methoxyphenyl) thienyl units on the antennas of ancillary ligands, respectively, were designed, synthesized, and characterized as sensitizers for dye-sensitized solar cells. The maximum absorption wavelength of MMR-1 is more red-shifted than that of MMR-2, but MMR-2 has a higher molar extinction coefficient, leading to better light harvesting. Under the same device-fabrication conditions, the photovoltaic performances of these sensitizers were evaluated while anchored on mesoporous TiO2 and compared to that of the benchmark N719. Both MMR-1 and MMR-2 exhibited comparable or even higher solar-to-electric conversion efficiencies η with respect to N719 when em-ployed as photosensitizers in DSSCs. Compared to MMR-1, MMR-2 exhibited better overall conversion efficiency, which was attributed to the electron-donating effect of the 4-methoxyphenyl group and the better absorptivity by harvesting higher-energy photons. Complex MMR-2 also showed higher open-circuit voltage VOC than MMR-1, which is likely due to the extension of the antenna of the ancillary ligand by inserting a phenyl group, which leads to less dye aggregation. The photovoltaic performance of MMR-2 was better, with a shortcircuit photocurrent density of 16.76 mA cm-2, a VOC of 0.673 V, a fill factor of 73.5 %, and an η value of 8.29 % with the addition of 0.5 M 4-tert-butylpyridine (TBP) compared to 8.18 % for N719. [ABSTRACT FROM AUTHOR]

Efficient and suitable methods for the synthesis of novel class of simple and fused heterocyclic compounds were prepared starting with 1-naphthyl-2-cyanoacetamide and commercially available reagents. The of 1-naphthyl-2-cyanoacetamide with sulfanylacetic acid furnished phenylthiazolinone derivative. Stirring of the starting compound with PhNCS afforded thiocarbamoyl derivative which underwent with chloroacetyl chloride to give thiazolinone derivative. 5-Aminopyrazole derivative was prepared by following mild procedures via refluxing the last thiocarbamoyl with hydrazine hydrate. Different synthetic approaches were discussed to obtain the novel fused pyrazolo[1,5- a]pyrimidine, 4 H-pyrazolo[3,4- d]pyrimidin-4-one moieties involving the reaction of the prepared 5-aminopyrazole with a) 1, 3-dielectrophilic centers (acetylacetone, acetoacetanilide), b) arylidines of malononitrile, and c) isothiocyanate derivatives. The action of iced sodium nitrite solution in acidic medium on the last 5-aminopyrazole gave pyrazolo[3,4- d][1,2,3]triazine. All novel structure were elucidated by different spectroscopic data (IR, MS, 1H, and 13C NMR) and elemental analysis. [ABSTRACT FROM AUTHOR]

(1,5-Dimethyl-3-oxo-2-phenyl-2,3-dihydro-1 H-pyrazol-4-yl)carbono-hydrazonoyl dicyanide was used as a key for the synthesis of novel pyrazole, isoxazole, pyrimidine, and pyridazine derivatives. The newly synthesized compounds were characterized by elemental analyses and spectral data (IR, 1H-NMR, 13C-NMR, and mass spectra). The compounds were tested for their in vitro against Gram-positive bacteria as ( Staphylococcus aureus and Bacillus subtilis) and Gram-negative bacteria ( Pseudomonas aeruginosa and Escherichia coli). The investigated compounds were tested against two strains of fungi Botrytis fabae and Fusarium oxysporum using diffusion agar technique. The biological results showed clearly that most of the synthesized compounds revealed mild to moderate activity against the used microorganisms. [ABSTRACT FROM AUTHOR]

The versatile hitherto reported 3-(1H-indol-3-yl)-1H-pyrazol-5-amine ( 4) was synthesized by the reaction of 3-cyanoacetylindole ( 3) with hydrazine hydrate in refluxing ethanol and used as a key for the synthesis of novel pyrazolo[1,5- a]pyrimidines via its reactions with appropriate 1,3-biselectrophilic reagents or through three-component with triethyl orthoformate and compounds possessing an activated methylene group. Besides, the applicability and synthetic potency of ( 4) to attain polyfunctionally substituted imidazo[1,2- b]pyrazole, pyrazolo[1,5- a][1,3]diazepine and pyrazolo[1,5- c][1,3,5]thiadiazine derivatives of an expected pharmaceutical interest have been investigated. The mechanistic aspects for the formation of the newly synthesized compounds are discussed. [ABSTRACT FROM AUTHOR]