Pyrazole

In the present study, a series of novel pyrazole‐thiazole hybrids (4a‐l) were designed, synthesized and assessed for their in vitro antimicrobial activity against both Gram‐positive and Gram‐negative pathogenic bacterial and fungal strains. Compounds derived from p‐CH3 phenyl (4b), p‐Br phenyl (4g), 8‐bromocoumarinyl (4k), and 6,8‐dibromocoumarinyl (4l) exhibited promising inhibitory activity against the tested bacterial strains with minimum inhibitory concentration (MIC)/minimum bactericidal concentration (MBC) spectrum of 1.9/7.8 μg/mL to 3.9/7.8 μg/mL. The compounds with p‐CH3 phenyl (4b), p‐OCH3 phenyl (4c), benzo[f]coumarinyl (4j), 8‐bromocoumarinyl (4k) substitutions showed their inhibitory potency against various Candida strains with MIC/minimum fungicidal concentration (MFC) values of 3.9/7.8 μg/mL. Also, anti‐biofilm and toxicity profile of the compounds was also tested. The biofilm inhibition results revealed that the compound 4 j exhibited promising activity with an IC50 value of 11.8 μM against S. aureus MTCC 96, while 4 k showed significant activity against S. aureus MLS16 MTCC 2940, K. planticola MTCC 530 and C. albicans MTCC 3017 with IC50 values of 12, 14 and 16 μM, respectively. The present study has emphasized that thiazole‐pyrazole hybrids with benzothiazole and coumarin scaffolds can be a novel and potent class of molecules with potential biological activities.

Four-component reactions of 3-amino-1,2,4-triazole or 5-amino-1H-pyrazole-4-carbonitrile with aromatic aldehydes and pyruvic acid or its esters under ultrasonication were studied. Unusual for such a reaction type, a cascade of elementary stages led to the formation of 7-azolylaminotetrahydroazolo[1,5-a]pyrimidines.

A series of fourteen novel 1,3,4-triarylpyrazoles were synthesized and evaluated for their antiproliferative activity against human breast cancer MCF7 cell line. Cells were exposed to different concentrations of compounds (0.1, 10, 100, 1000 µM) for 72 hours. Then the viability of treated cells was determined using MTT technique. Compound 7a was found to exhibit significant antiproliferative activity (IC50 = 6.95 μM). Using flow cytometric analysis, compound 7a was observed to induce apoptosis and to block the cell cycle at G2/M phases in MCF7 cells. 3D-Pharmacophore modeling and quantitative structure-activity relationship (QSAR) analysis were combined to explore the structural requirements controlling the observed anti-tumor properties.

The comparative analysis of the stimulating effect of low molecular weight heterocyclic compounds, derivatives of pyrimidine, pyrazole, isoflavones, pyridine, oxazolopyrimidine, oxazole and plant hormones auxins IAA (1H-Indol-3-ylacetic acid) and NAA (1-Naphthylacetic acid) on germination of seeds and growth of seedlings of flax (Linum usitatissimum L.) cultivars Ukrainian 3 and Svitanok was conducted. The specific auxin-like stimulating effect of chemical heterocyclic compounds on the basic processes of flax seedlings growth: cell division, cell proliferation, cell elongation and cell differentiation was found. The growth parameters of flax seedlings grown on water solution of chemical heterocyclic compounds used at the concentrations 10-8 M and 10-9 M were similar or higher of the growth parameters of flax seedlings grown on distilled water (control) or on water solution of auxins IAA and NAA used at the same concentrations 10-8 M and 10-9 M. The obtained results proved the possibility of practical application o f derivatives of pyrimidine, pyrazole, isoflavones, pyridine, oxazolopyrimidine and oxazole for intensification of vegetative growth of flax.
Keywords: Linum usitatissimum L., auxins IAA and NAA, pyrimidine, pyrazole, isoflavones, pyridine, oxazolopyrimidine, oxazole.

A simple synthetic method is reported for the preparation of some new phosphorus macrocycles in which the pyrazole rings are appended to a phosphorus atom. The methodology is based on the cyclocondensation reaction of bis(4-formylpyrazolyl) phosphine oxide(1a, 1b) with nitrogen nucleophiles that contain active terminal amino groups. The antimicrobial activities of the synthesized compounds were assayed.

The reactions of 2-aminothiophenol with acetylacetone in refluxing DMSO or ethanol was investigated. Treatment of 1 with enaminone 5 gave benzothiazine derivative 6. A reasonable mechanism to account for the formation of pyridone derivative 11 by treatment of 2 with malononitrile. Reactions of 2 with cyanoacetic hydrazide, thiosemicarbazide, and hydrazine hydrate and phenyl hydrazine afforded the compounds 13, 15 and, 17a-b respectively. Condensation of 13 with 4-methoxy benzaldehyde gave 18. The latter compound reacted with malononitrile gave pyridone derivative 19. A reasonable mechanism account for the formation of pyrazolo[3,4-b]pyridine derivative 20 from the reaction of 13 with DMF-DMA via cleavage of a thiazine ring of benzothiazine. The structures of all newly synthesized compounds elucidated by elemental analysis 1 H-NMR and 13 C-NMR spectra, Ms and X-ray crystallographic investigations. The reported crystal structures of these novel benzothiazine derivatives are expected to be a remarkable contribution to the crystallographic database of heterocyclic compounds.

New  series  of  2-heterocycle-substituted  benzimidazole  having  a
pyrazolo  [3,  4-d]  pyrimidine  nucleus  have  been  synthesized  by
reacting  2-(chloromethyl)  benzimidazole  with  hydrazine  hydrate  to
form  compound  (1).  The  vital  compound  in  this  synthesis  1-((benzoimidazol-2-yl)methyl)-3-methyl-pyrazol-5-one was  obtained
by  reacting  compound  (1)  with  ethyl  acetoacetate,  and  was  used  in
the Biginelli multi-component cyclo condensation reaction with eight
derivatives of benzaldehyde in presence of urea  to  form pyrimidine
derivatives (3-10).
The products were characterized by C.H.N analyses,  I.R spectra and
1
HNMR spectrum.
Antibacterial activity of some prepared compounds against two types
of  bacteria: Staphylococcus  aureus (Gram  positive)  and
Pseudomonas  aeruginosa (Gram  negative).  Some  the  compounds
showed high inhibition activity against bacteria.