The effect of various acrylonitriles and related compounds on prostaglandin biosynthesis

Nitrogen-Enriched Biguanidine-Functionalized Cobalt Ferrite Nanoparticles as a Heterogeneous Base Catalyst for Knoevenagel Condensation under Solvent-Free Conditions

Designing efficient, economical heterogeneous catalysts for the Knoevenagel condensation reaction is highly significant owing to the importance of reaction products in industries as well as pharmaceutics. Herein, we have designed and synthesized biguanidine-functionalized basic magnetically retrievable cobalt ferrite nanoparticles (CFNPs) for the synthesis of Knoevenagel condensation products using benzaldehydes and active methylene compounds (malononitrile/ethyl cyanoacetate/cyanoacetamide). Several advanced techniques, such as Fourier transform infrared (FT-IR), thermogravimetric analysis (TGA), powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and vibration sample magnetometry (VSM), were utilized to precisely characterize the catalyst. The robust features of the current approach involve outstanding catalytic performance, solvent-free reaction conditions, ease of catalyst retrievability, easy workup procedure, large substrate tolerance, high turnover frequency (TOF) values (up to 486.88 h-1), values of green chemistry metrics such as E-factor (0.15), reaction mass efficiency (RME) value (87.07%), carbon efficiency (93.4%), and atom economy (AE) value (88.10%) close to their ideal values, and recyclability up to eight runs without a considerable reduction in activity, boosting the appeal of this approach from a commercial and ecological point of view.

Arylcyanomethylenequinone Oximes: An Overview of Synthesis, Chemical Transformations, and Biological Activity

Quinone methides are a class of biologically active compounds that can be used in medicine as antibacterial, antifungal, antiviral, antioxidant, and anti-inflammatory agents. In addition, quinone methides have the potential to be used as pesticides, dyes, and additives for rubber and plastics. In this paper, we discuss a subclass of quinone methides: methylenequinone oximes. Although the first representatives of the subgroup were synthesized in the distant past, they still need to be additionally studied, while their chemistry, biological properties, and perspective of practical applications require to be comprehensively summarised. Based on the analysis of the literature, it can be concluded that methylenequinone oximes exhibit a diversified profile of properties and outstanding potential as new drug candidates and reagents in organic synthesis, both of electrophilic and nucleophilic nature, worthy of wide-ranging further research.

Synthesis of benzylidenemalononitrile by Knoevenagel condensation through monodisperse carbon nanotube-based NiCu nanohybrids

Monodisperse nickel/copper nanohybrids (NiCu@MWCNT) based on multi-walled carbon nanotubes (MWCNT) were prepared for the Knoevenagel condensation of aryl and aliphatic aldehydes. The synthesis of these nanohybrids was carried out by the ultrasonic hydroxide assisted reduction method. NiCu@MWCNT nanohybrids were characterized by analytical techniques such as X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HR-TEM), and Raman spectroscopy. According to characterization results, NiCu@MWCNT showed that these nanohybrids form highly uniform, crystalline, monodisperse, colloidally stable NiCu@MWCNT nanohybrids were successfully synthesized. Thereafter, a model reaction was carried out to obtain benzylidenemalononitrile derivatives using NiCu@MWCNT as a catalyst, and showed high catalytic performance under mild conditions over 10-180 min.

Green Synthetic Methodology of (E)-2-cyano-3-aryl Selective Knoevenagel Adducts Under Microwave Irradiation

Background:

The Knoevenagel condensation is an important reaction in organic chemistry because of its capacity to form new C-C bonds and its products are mainly used in organic synthesis as intermediates, due to the large number of reactions they can undergo. Based on the importance of the Knoevenagel adducts, a sustainable synthetic methodology was developed employing microwave irradiation.

Objective:

Develop a synthetic methodology employing microwave irradiation and green solvents to obtain Knoevenagel adducts with high yields.

Methods:

Knoevenagel condensation reactions were evaluated with different basic catalysts, as well as in the presence or absence of microwave irradiation. The scope of the reaction was expanded using different aldehydes, cyanoacetamide or methyl cyanoacetate. The geometry of the formed products was also evaluated.

Results:

After the optimization process, the reactions between aldehydes and cyanoacetamide were performed with triethylamine as catalyst, in the presence of microwave irradiation, in 35 minutes, using NaCl solution as solvent and resulted in high yields 90-99%. The reactions performed between aldehydes and methyl cyanoacetate were also performed under these conditions, but showed better yields with EtOH as solvent 70-90%. Finally, from X-ray analysis, the (E)-geometry of these compounds was confirmed.

Conclusion:

In this study we developed synthetic methodology of Knoevenagel condensation using triethylamine, green solvents and microwave irradiation. In 35 minutes, products with high yields (70- 99%) were obtained and the (E)-geometry of the adducts was confirmed.

Solvent-free condensation of phenylacetonitrile and nonanenitrile with 4-methoxybenzaldehyde: optimization and mechanistic studies

The condensation of phenylacetonitrile with 4-methoxybenzaldehyde can be carried out by two solvent-free methods: i) using neat powdered KOH at room temperature with equivalent amounts of aldehyde, nitrile and base for 3 min, and ii) using K2CO3 in the presence of a phase transfer agent for 3 min under microwave activation or conventional heating. By extending the reaction time up to 10 min, four different products were obtained from phenyl or nitrile group migration. With nonanenitrile, only the second method could be applied to give two kinds of condensed compounds with or without phenyl (or nitrile) group migration. The intervention of non-thermal MW-specific effects was proved in some cases and interpreted.

Relative involvement of protein kinase C and of the estrogen receptor in the cytotoxic action of a population of triphenylethylenes on MCF7 cells as revealed by correspondence factorial (CF) analysis

A multivariate statistical method, correspondence factorial (CF) analysis, was used to examine the correlations among the protein binding and cell proliferation effects of a series of 36 di- and triphenylethylenes (DPEs and TPEs). The analysis was applied to a study which measured their competition for estradiol binding to cytosol estrogen receptor (ER), their influence on protein kinase C (PKC) activity under different conditions of enzyme activation, their ability to promote the growth of a breast cancer cell line and to inhibit growth at high concentrations (cytotoxicity). The CF analysis revealed several levels of correlation. First, it distinguished those molecules within the population that stimulated rather than inhibited PKC activity. Second, it made apparent a strong correlation between cytotoxicity and inhibition of Ca++ and phosphatidylserine-dependent PKC activity, which was most marked when the enzyme had been activated by diacylglycerol indicating that PKC inhibition under physiological conditions might contribute to the overall cytotoxicity of these compounds. Third, a lower level of correlation was established between competition for ER binding and cytotoxicity. Taken together, the results suggest that MCF7 cells might be most sensitive to a cytotoxic effect of TPEs (via PKC and other targets) when they at the same time decrease estrogen-stimulated proliferation via an ER-mediated antiestrogenic effect.

New prostaglandin synthetase inhibitors--di-and triphenylacrylonitriles

16 triphenylacrylonitriles (TPE) or diphenylacrylonitriles (DPE) were synthesized by condensation of various benzophenones or benzaldehydes with various phenylacetonitriles. The pharmacological potency of these compounds was studied by incubation of bovine seminal vesicle microsomes and PG-RIA. The results showed that the potency of inhibition of PG biosynthetase of DPE was stronger than that of TPE. Compounds with electron-releasing functional groups were proved to be more effective than those with electron-attracting groups. Compound DPE-9 was the most active one, the potency of which was 40 times stronger than that of naproxen. The structure of some compounds has been analysed by X-ray diffraction. The relationship between structure and activity was investigated by means of X-ray diffraction, UV and NMR.

Inhibition of platelet aggregation by novel triphenylethylene analogs

The present study has evaluated the effect of some newly synthesized triphenylethylene (TPE) analogs on platelet arachidonic acid metabolism and function. All compounds tested inhibited arachidonic acid induced platelet aggregation and several were superior to aspirin in their relative potency. Introduction of a carboxyl function into the alpha-ring, which should enhance binding according to proposed structural models for cyclooxygenase inhibitors, was not found to be beneficial. Increased structural rigidity, which resulted from covalent linkage of two aromatic rings in this series, did not eliminate anti-aggregatory properties.