Pyrazole Research Articles

ChemInform Abstract: A Carbanion Induced Synthesis of Highly Congested Pyrazole and Imidazole Containing Heterocycles.

AbstractEnamines (III) as well as congested di‐ (V), penta‐ (X), and hexacyclic pyrazoles (XII) are synthesized.

Studies in Heterocyclic Compounds -Part VIII

Different azo compounds, 1-(m-nitrophenyl)-3-(p-bromophenyl)-and 1-(m-nitrophenyl) 3-(p-chlorophenyl)-2-(substituted sulphonamidobenzeneazo) propane-1,3-dinoes on condensation with hydrazine hydrate (100%), phenylhydrazine, p-nitrophenyllhydrazine and benzoylhydrazine yield the corresponding 1-simple/substituted-3-(m-nitrophenyl)-5-(p-bromo chlorophenyl)-4-(substituted sulphonamidobenzeneazo) pyrazoles. The homogeneity and purity of these was confirmed by TLC and these on screening in vitro against S. aureus and E. coli were found to exhibit antibacterial activity.

Synthesis and Characterization of Some Novel 4-Aryloxy Substituted Pyrazoles

Synthesis and Characterization of Some Novel 4-Aryloxy Substituted Pyrazoles

ChemInform Abstract: Some New Pyrazole and Pyrazolopyrimidines: Synthesis and Antimicrobial Evaluation.

AbstractThe novel β‐enaminonitrile derivative (III) is synthesized and can be applied as precursor for the preparation of pyrazoles pyrazolopyrimidines and some of their corresponding N‐acyclic nucleosides.

CYCLOCONDENSATION OF 2-PHENACYL-1H-BENZIMIDAZOLE WITH ACYLHYDRAZINES: SYNTHESIS AND TAUTOMERISM OF 2-(PYRAZOL-4-YL)-1H-BENZIMIDAZOLES

The previously unknown 2-(pyrazol-4-yl)benzimidazoles containing aryl groups in the pyrazolyl ring have been obtained by the reaction of 2-phenacyl-1H-benzimidazole with aroylhydrazines. The compounds with nitrophenyl and pyridyl substituents in the pyrazole ring show pyrazolyl tautomerism with differences in the 1 H NMR spectra. A semi-empirical method is proposed to determine the tautomeric composition of the synthesized pyrazoles. Authors: I. B. Dzvinchuk, A. V. Vypirailenko, V. V. Pirozhenko, and M. O. Lozinsky. English Translation in Chemistry of Heterocyclic Compounds , 1999, 35 (11), pp 1319-1324 http://link.springer.com/article/10.1007/BF02252001

ChemInform Abstract: Synthesis of Substituted 1H‐Indazoles by Pyrazole Anellation to an Arene.

ChemInform Abstract: Synthesis of Substituted 1H‐Indazoles by Pyrazole Anellation to an Arene.

Salen–Cu(II) Complex Catalysed N-Arylation of Pyrazole under Mild Conditions

Three inexpensive and air-/moisture-stable complexes (Salden)Cu (Salden = N, N’-bis(salicylidene)-1,2-dimethylethylenediamine), (Saldch)Cu (Saldch = N, N’-bis(salicylidene)-1,2-cyclohexenediamine),...

Synthesis of Pyrazoloisoquinolines from Alkynes and Pyrazoles

Key words copper catalysis - pyrazoloisoquinolines - annulation - alkynes

Estradiol regulates the expression of small conductance Ca(2)+ activated K(+) channel 3 in rat colonic smooth muscle cells in an estrogen receptor α-dependent manner

To explore the effects and possible mechanism of 17β-estradiol on the expression of small conductance Ca(2+) activated K(+) channel 3 (SK3) in rat colonic smooth muscle cells (SMC). The SMC isolated from male SD rats by enzymolysis were cultured. And double immunofluorescence staining was used to detect the co-expression of SK3 and α-actin. Colonic SMC were cultured with different concentrations of 17β-estradiol for 24 h or with 50 nmol/L 17β-estradiol at different time points respectively. The expressions of SK3 in colonic SMC were measured by real-time quantitative reverse transcription (qRT)-PCR and Western blotting. The effects of estrogen receptor (ER) inhibitor ICI 182780, albumin bovine serum-17β-estradiol (BSA-E2), ERα selective agonist propyl pyrazole triol (PPT) and ERβ selective agonist diarylpropionitrile (DPN) on SK3 expression were observed. Double immunofluorescence staining showed that SK3 and α-actin co-expressed in cultured colonic SMC. The expression of SK3 of 17β-estradiol at different concentration (10, 50 nmol/L) significantly higher than the control group (protein: 0.217 ± 0.030 and 0.321 ± 0.077 vs 0.103 ± 0.063, mRNA: 1.872 ± 0.606 and 2.967 ± 0.659 vs 0.813 ± 0.202, all P < 0.05). And 50 nmol/L was the most effective in vitro concentration. The peak expression of SK3 appeared at 12 and 24 hour (2.91 and 3.30-fold in protein vs 3.46 and 3.37-fold in mRNA respectively, all P < 0.05). The protein levels of SK3 in ICI 182780 plus 17β-estradiol group was less than 17β-estradiol group (0.111 ± 0.050 vs 0.351 ± 0.084, P < 0.05). But it was not influenced by BSA-E2. The expressions of SK3 in PPT and E2 groups were both higher than control group (0.270 ± 0.071, 0.309 ± 0.052 vs 0.087 ± 0.018, both P < 0.05) . However DPN had no effect on SK3 protein levels. SK3 is localized in rat colonic SMC. And 17β-estradiol increases its expression in an ERα-dependent manner.

Heteroannulative C-H Activation Route to Pyrazoles and Indazoles

Key words pyrazoles - indazoles - copper catalysis - C–H functionalization

Performance Characteristics of Pyrazole as an Effective Dopant in a Blended Polymer Electrolyte for Nanocrystalline Dye-Sensitized Solar Cell Applications

Thin films of nanocomposite blended solid polymer electrolyte consisting of polymethyl methacrylate (PMMA)/polyvinylidene fluoride (PVDF), potassium iodide (KI) and iodine (I 2) as redox couple and pyrazole (PYR) as dopant were prepared using solution casting technique. The consequences of inclusion of PYR within PMMA/PVDF/KI/I 2 were investigated in terms of photovoltaic performance of the cell whereas the PYR impregnated polymer electrolyte solution when introduced into dye-sensitized solar cells (DSSCs) exhibited an overall energy-conversion efficiency of 5.5% at room temperature under AM1.5 illumination.

FeBr3-Catalyzed C-H Activation Route to Indazoles and Pyrazoles

Key words indazoles - pyrazoles - iron catalysis - C–H activation

Study of Fragmentation Mechanisms of Pyrrolo[3,4-c]pyrazole Derived Aurora Kinase Inhibitors by ESI-QTOF-MS/MS

吡咯并[3,4-c]吡唑衍生的Aurora激酶抑制剂是具有良好开发前景的新型抗肿瘤药物之一.采用电喷雾-四级杆飞行时间串联质谱技术,对4种吡咯并[3,4-c]吡唑衍生的Aurora激酶抑制剂在电喷雾质谱中的裂解途径及其碎片离子结构进行研究.实验结果表明：吡咯并[3,4-c]吡唑衍生物拥有4个可能的质子化模式,不同的质子化作用会产生不同的碎片离子,且吡咯并[3,4-c]吡唑衍生物N（5）—CO键断裂所产生的碎片离子相对丰度较高,可以作为药物代谢动力学及酶学水平研究中质谱的特征性碎片离子.需要指出的是,化合物3,4能够分别丢失一分子水形成碎片离子[M＋H-H2O]＋,根据高分辨质谱和理论计算结果我们推测该过程是由质子化作用发生在酰胺氧原子上引发的,而CID条件下N（5）—CO键的进一步断裂可产生相对丰度较高的碎片离子.

Synthesis of triazole, pyrazole, oxadiazine, oxadiazole, and sugar hydrazone-5-nitroindolin-2-one derivatives ( part I)

Objective The aim of part I is the synthesis of different series of 1H-1,2,4-triazol-3-yl)phenylimino)(methylbenzyl)-5-nitroindolin-2-ones, 1H-pyrazole-1-carbonyl)phenylimino)-1-(p-methylbenzyl)-5-nitroindolin-2-ones, 3-(4-(1,3,4-oxadiazin-6-one)phenylimino)-1-(p-methylbenzyl)-5-nitroindolin-2-ones, 1,3,4-oxadiazol-2-yl)phenylimino)-1-(p-methylbenzyl)-5-nitroindolin-2-ones, and 4-(-1-(p-methylbenzyl)-5-nitro-2-oxoindolin-3-ylideneamino) sugar hydrazone derivatives (4–13) through the reaction of 4-[1-(p-methylbenzyl)-5-nitro-2-oxoindolin-3-ylidineamino]benzohydrazide (3) with different reagents to be evaluated biologically. Materials and methods Derivatives of (1H-1,2,4-triazol-3-yl)phenylimino)-1-(p-methylbenzyl)-5-nitroindolin-2-one and (1H-pyrazole-1-carbonyl)phenylimino)-1-(p-methylbenzyl)-5-nitroindolin-2-one (4–6) were prepared by the reaction of 4-[(1-(p-methylbenzyl)-5-nitro-2-oxoindolin-3-ylideneamino)] benzohydrazide (3) with benzyl, benzoyl isothiocyanate, or acetyl acetone to form 1H-1,2,4-triazole and 1H-pyrazole-5-nitroindolin-2-one derivatives. The reaction of 3 with ethyl bromoacetate, ethyl acetoacetate, or acetyl chloride afforded 1,3,4 oxadiazin-6-one, 3-methyl-5-oxo-4,5-dihydro-1H-pyrazole, or 1,3,4-oxadiazole-5-nitroindolin-2-one derivatives (7–9), respectively. Sugar hydrazone-5-nitroindolin-2-ones (10–13) were archived by the reaction of 3 with D-glucose, D-mannose, D-arabinose, and D-ribose using both conventional and green chemistry. Results and conclusion Conventional and microwave methods used for the synthesis of various triazole, pyrazole, oxadiazine, oxadiazole, and sugar hydrazone-5-nitroindolin-2-one derivatives were applied for the synthesis of compounds 4–13. These methods were simple and gave good yields of the target compounds in short reaction times.

New pyrazole derivatives of potential biological activity

Chloro-3-methyl-1-phenyl-1H-pyrazole-4-carboxaldehyde ( 1) was reacted with hydrazine hydrate and thiosemicarbazide to afford the corresp onding hydrazones 2 and thiosemicarbazones 4. The latter compounds were used to obtain the pyra zole derivatives 3, 5-7. A series of azines 8a-e were obtained by reacting 2 with aromatic aldehydes. Potassium permanganate oxidation of 1 gave the acid 9, which was transformed into the corresponding acid azide 11 then used to prepare diverse urea derivatives 13-18 via Curtius reaction .

Ultrasound-promoted clean synthesis of 1-thiocarbamoyl-3-(2-hydroxyphenyl)-5-aryl-4,5-dihydro-1H-pyrazoles

of important biological and pharmaceutical activities. In recent years, we described the synthesis of many heterocycles by non-traditional conditions, such as microwaves and ultrasound. In particular, the beneficial effects of ultrasonic irradiation are playing an increasing role in process chemistry, especially in cases where classical methods require drastic conditions or prolonged reaction times. These observations and our interest in clean production of heterocyclic compounds prompted us to apply ultrasound in the preparation of 1-thiocarbamoyl-3-(2-hydroxyphenyl)-5-aryl-4,5-dihydro-1H-pyrazoles. The best condition for preparing the target pyrazoles ( 5a-c ) was achieved when two equivalents of both KOH and thiosemicarbazide and 1 equivalent of the chalcones/flavanones ( 3,4a-c ) were sonicated for 30 minutes, affording the desired pure product in good yield (Scheme). In conclusion, we have developed a mild, convenient and environmentally friendly protocol for the preparation of target compounds under ultrasonic irradiation. Significant advantages of the method include the fact that: (i) the reaction is simple to execute; (ii) the products are isolated in good yields (61-76%); (iii) the work-up is very simple and (iv) the reaction time is short (30 min) .

Ultrasound-promoted iodination of pyrazoles in aqueous medium

Several pharmacological activities have been devoted to pyrazole containing molecules. In particular, 4-iodopyrazoles have been employed as key starting materials in cross-coupling chemistry and metal-iodine exchange reactions that focus on the synthesis of such biologically important compounds. Unfortunately, existing methods for the synthesis of 4-iodopyrazoles are not in agreement with the environmental requirements due to a series of drawbacks including the use of large excess of reagents, the generation of toxic waste and long reaction times. Recently, we developed a fast and mild reaction condition for the iodination of aromatic compounds using an I 2 /H 2 O 2 system water as a nonflammable and innocuous solvent and ultrasonic irradiation as energy source. In this work, we present the application of this methodology for the iodination of pyrazoles (Scheme). Initially, a series of pyrazoles were efficiently prepared starting from 1,3-dicarbonyl compounds and hydrazines under ultrasonic irradiation. Three examples from the pyrazoles were subjected to the iodination condition shown above. Iodopyrazoles were obtained in 63-65% yields.

Potent anti-inflammatory and analgesic activities of new derivatives of chalcone, pyridine, pyrazole, and isoxazole incorporated into 5,6,7,8-tetrahydronaphthalene

Objective Synthesis of new series of 5,6,7,8-tetrahydronaphthalene derivatives conjugated with chalcone, pyridine, pyrazole and isoxazole functionalities hoping to circumvent the unwanted ulcerogenic and other side effects of the already used nonsteroidal anti-inflammatory drugs. Background Most currently used nonsteroidal anti-inflammatory drugs (NSAIDs) suffer from limitation in their therapeutic uses, since they cause gastrointestinal and renal side effects related to inhibition of cyclooxygenase1 (Cox1) in tissues where prostaglandins exert physiological effects. Methodology Reaction of 2-acetyl tetralin (1) with some aromatic aldehydes in the presence of malononitrile yielded 2-amino-3-cyanopyridine derivatives 2a–c. Condensation of compound 1 with aromatic aldehydes afforded the chalcone derivatives 3a–c. Then, compound 3a reacted with hydrazine hydrate or phenyl hydrazine and yielded pyrazoline derivatives 4 or 5, respectively. Also, the reaction of compound 3c with hydroxylamine hydrochloride afforded the isoxazole derivative 6. Anti-inflammatory properties of the synthesized compounds were evaluated in vivo utilizing formalin induced paw edema method in rats, analgesic activities were tested via both hot plate and writhing methods. Results Derivatives 2c and 3c revealed promising results when the anti-inflammatory, analgesic, and ulcerogenic activities of the synthesized compounds were evaluated. All of the compounds induced significant central and peripheral analgesia. The derivatives 2a, 2c, 3a, 3b, 3c, 5, and 6 showed higher activity than the standard ibuprofen.

ChemInform Abstract: “Reported, but Still Unknown”. A Closer Look into 3,4‐Bis‐ and 3,4,5‐Tris(trifluoromethyl)pyrazoles.

AbstractStraightforward routes to title compounds (VI) and (XIV) are reported.

ChemInform Abstract: Cyanoacetamide in Heterocyclic Chemistry: Synthesis, Antitumor and Antioxidant Activities of Some New Benzothiophenes.

AbstractA variety of new iminocoumarins, acrylamides and pyrazoles bearing a tetrahydrobenzothiophene moiety are synthesized using cyanoacetamide (III) as key intermediate.