Organic Chemistry Research
Volume:4 Issue: 2, Spring 2018

An environmentally friendly, one-pot, three-component synthesis of 8,10-dimethyl-12-aryl-12H-naphtho[1′,2′:5,6]pyrano[2,3-d]pyrimidine-9,11-diones was achieved via coupling aromatic of aldehydes, β-naphthol and 6-amino-1,3-dimethyl uracil in the presence of formic acid as a catalyst under solvent-free conditions at 90 °C. This method has several advantages, such as efficiency, good yield, short reaction time, cleaner reaction profiles, ease of product isolation, operational simplicity and inexpensive, effective and catalyst.the formula is not displayed correctly!

Novel N-amino benzylthiolates were synthesized via multicomponent reaction of malononitrile, isothiocyanates and benzyl halides under conventional and solvent-free conditions. Various electron-donating and -withdrawing substitutes within both isothiocyanates and benzyl halides were used to demonstrate the efficiency of new methodology. A broad spectrum of antibacterial and antifungal activities were observed especially within benzyl halides containing electron-withdrawing aryl substituents.

Convenient procedure for the synthesis of corresponding pyrano[2,3-d]pyrimidine derivatives were developed via one-pot three-component reaction of aryl aldehyde derivatives, malononitrile with barbituric acids in the presence of copper (II) chloride dihydrate (CuCl2.2H2O) as highly efficient Lewis acid catalyst. This protocol has advantages such as readily and inexpensive catalyst, high reaction yields, eco-friendly solvent and high atom-economy.

In current study, the synthesis and characterization of novel thermally stable polyimides (PIs) containing an 1,3,4-oxadiazole moiety based on a diamine, i.e. 2,5-bis(3-amino-4-methyl benzene)-1,3,4-oxadiazole (BAMO), have been reported. The polymers were characterized using FT-IR and elemental analysis (CHN). Thermal and mechanical behaviours of the prepared PIs were studied by thermo-gravimetric analysis/differential thermal analysis TGA/DTA, and dynamic mechanical thermal analysis (DMTA). The obtained results reveal PI (4), which was obtained from BAMO and 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (6FDA) exhibited the best thermal and mechanical properties.

Magnetic Cellulose/Fe3O4/Co3O4 nanocomposite as a new catalyst was synthesized and characterized by FT-IR, XRD, TGA, SEM, TEM, ICP-AES and VSM techniques. The catalytic activity of this heterogeneous catalyst was studied through one-pot synthesis of 1-((benzo[d]thiazol-2-ylamino)(aryl)-methyl)naphthalen-2-ol derivatives from three component reactions of aromatic aldehydes, 2-aminobenzothiazole, and β-naphthol. This benign and economical nanocatalyst was easily recovered using an external magnet and reused in at least five successive runs with no significant loss of activity and provided clean production in a short reaction time.

Ionic liquid 1,3-disulfonic acid imidazolium trifluoroacetate ([Dsim][TFA]) has been exploited as a highly efficient catalyst for the one-pot pseudo five-component reaction of phenylhydrazine (2 eq.) with ethyl acetoacetate (2 eq.) and arylaldehydes (1 eq.) in ethanol (reflux conditions). In this reaction, 4,4′‐(arylmethylene)‐bis(3‐methyl‐1‐phenyl‐1H‐ pyrazol‐5‐ol)s have been obtained in high yields and relatively short reaction times. High efficacy of [Dsim][TFA] can attributed to dual-functionality (possessing three acidic and one basic sites). A plausible and attractive mechanism based on dual-functionality of the catalyst has been proposed.

Silica sodium carbonate (SSC) has been used as a valuable silica-supported catalyst for the preparation of a range of known and novel pyrano coumarins via the three-component reactions of aryl aldehydes, active methylene compound (malononitrile or ethyl cyanoacetate), and hydroxycoumarin (5,7-dihydroxy-4-substituted coumarins or 4-hydroxycoumarin). The heterogeneous catalyst showed much the same efficiency when employed in following reaction runs.

The aim of present study is to determine the content of some phytochemicals in stem and leaf extracts of the medicinal plant of Glycyrrhiza glabra and design a green method for biosynthesis of silver nanoparticles by these extracts as stabilizers and bioreducers. The properties of the synthesized silver nanoparticles (AgNPs) were monitored by using Ultraviolet-Visible absorption spectroscopy (UV-Vis) and fully characterized by scaning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The effect of different parameters including concentration of the extracts and silver nitrate salt, reaction time, temperature and thier intraction on bio-reduction process were also disscused. In addition, antibacterial and antifungul activities of the extracts and the synthesized AgNPs were assessed against 4 positive and negative bacteria by disc diffusion method and also the fungus Fusarium oxysporum. Results indicated that the bio-reduction process was relatively fast and the resulting nanoparticles were nearly spherical in their shapes with the size range of 5-45 nm. The best conditions for biosynthesis were achieved in 1-3 mmol AgNO3, 60 °C temperature and 4 h reaction time. All the extracts and their corresponding nanoparticles had good inhibition activities against bacteria tested. However, the extracts showed more inhibition activity against Gram positive bacteria, while the synthesized AgNPs were more active against Gram negative bacteria. This is the first report on the green synthesis of AgNPs using G. glabra extract followed by an estimation of their biological activities may open new insight in the applications of these nanoparticles for various purposes.

A novel azo-Schiff base ligand (L) was prepared by reacting 2-hydroxy-5-(pyridine-4-yldiazenyl) benzaldehyde with 1,2-phenylenediamine. Moreover, Silver nanoparticles (Ag-NPs) and Cadmium sulfide nanoparticles (CdS-NPs) were prepared by employing azo-Schiff base ligand (L) as capping and reducing agent. The solid-state fluorescence spectroscopy was used to investigate the interaction between L with one of the nanomaterials (CdS-NPs). The fluorescence studies showed that L suppresses the CdS-NPs fluorescence. The antibacterial and antifungal activities of mentioned nanoparticles were determined against different bacteria and plant fungal strains and the obtained results were compared. The azo-Schiff base ligand (L) only exhibited antibacterial activity against B. cereus as Gram-positive bacterium. L-Ag-NPs had moderate to high antibacterial properties for both Gram-negatives and Gram-positives species. Moreover, L-CdS-NPs showed activity against B. cereus as a Gram-positive and E. coli as a Gram-negative baterium. All the described compounds showed antifungal activity against the fungal strains tested.

TiCl4/nano-cellulose as a biodegradable and eco-friendly Lewis acid catalyst was synthesized via reaction of nano-cellulose and TiCl4. This catalyst was characterized and used for synthesis of asymmetric highly functionalized tetrahydropyridines via a five-component condensation reaction of p-substituted anilines, aldehydes and ethyl acetoacetate under solvent-free condition. Simple methodology, eco-friendly catalyst, clean procedure, easy work-up and high yields are some of the important advantages of this protocol.

The one-pot synthesis of symmetrical triaryl amines using aryl halides and 5-Methyl-1,3,4-Thiadiazole-2-Amine as a nitrogen-transfer reagent is reported. Copper oxide nanoparticles that does not require the presence of any additional ligand, improved rate and facility of the synthesis of triaryl amines. The introduction of a new N-source, using green solvents PEG/H2O, normal atmospheric conditions and excellent yields under mild reaction conditions are other important features of this work.

The reaction of dibenzoylacetylene with 4-alkylaminocoumarins in THF/H2O (50:50) lead to 4-(alkylamino)-3-(1,4-dioxo-1,4-diphenylbut-2-en-2-yl)-2H-chromen-2-one derivatives in good yields. When the reaction carried-out in DMSO the cyclized products 2-hydroxy-1-alkyl-3-(2-oxo-2-phenylethylidene)-2-phenyl-2,3-dihydrochromeno [4,3-b] pyrrol-4(1H)-ones were formed in good yields.the formula is not displayed correctly!