Organic Chemistry Research
Volume:6 Issue: 1, Spring 2020

An efficient methodology for the preparation of 2-aminothiazoles is achieved by one-pot reaction of methylcarbonyls, thiourea and iodine in the presence of an aluminum oxide nanoparticle as an active nanocatalyst at 85 °C in DMSO solvent. Al2O3 nanoparticles have been prepared via co-precipitation method and their structures were confirmed using Fourier transform infrared radiation (FT-TR), X-ray diffraction (XRD), scanning electron microscopic (SEM), and energy-dispersive analysis of X-ray (EDAX) analyses. Advantages of this efficient synthetic approach include higher purity and excellent yield of products, easy isolation of products and convenient manipulation.

The one-pot four component synthesis of 3-(Imino)-2,3-dihydropyrrolo[2,1-a]isoquinoline-1,1(10bH)-dicarbonitrile derivatives via a catalyst-free reaction between aryl aldehydes, malononitrile, isoquinoline and isocyanides was successfully conducted in glycerol as a benign, nontoxic and biodegradable promoting reaction medium. The progress of the reaction with two different common purification methods were investigated. Moreover, synthesized products were examined as chemical sensors for the detection of a wide range of metal ions and it was successful for the detection of Co2+ ions.

4-phenylsulfonyl-2,3,5,6-tetrachloropyridine was synthesized by the reaction of pentafluoropyridine with sodium benzenesulfonate under ultrasonic irradiation. This new methodology provides the excellent yield in a very short reaction time at 0 oC. In the presence of ultrasound irradiation, the yield was 90% after 8 min, by using our previously established method the yield was 85% after 10 h. Also, in this research, the substituent effect in meta and para position of phenyl ring on intramolecular halogen bond strength has been investigated by theoretical studies. The calculations were performed with Gaussian09 software in M05-2X/6-311++G(d,p) level. The results show that one of the oxygen atoms of the SO2 group is co-planer with the pyridine ring and the other oxygen atom is out of this plane. Also, it is observed that the electron-withdrawing groups in meta and para positions reinforced the halogen bond that the oxygen atom of the SO2 group is co-planer with pyridine ring. An opposite behavior is observed for electron-donating groups.

A detailed study on the formed complexes from interaction between vitamin B3 with parent uracil and anticancer uracil's is performed using M06-2X/6-311++G(d,p) and B3LYP/6-311++G(d,p) levels of theory. In the studied systems, the uracil's can be placed in three preferential interaction sites (A1–A3) in the vicinity of the vitamin B3. For each uracil group, three configurations corresponding to energetic local minima are obtained. Among the various hydrogen bonding sites, the A1 region of uracil's shows the strongest interactions at both levels of theory. The analyzed dimers are also stabilized by two hydrogen bonds (H-bonds). The predicted H-bonds in the formation of complexes are: O∙∙∙H-N and O(S)∙∙∙H-O. The topological properties of the electron density distribution are also analyzed in terms of the Quantum Theory of “Atoms in Molecules” (QTAIM). Furthermore, the natural bond orbital (NBO) analysis is applied to get a more precise insight about the nature of the H-bond interactions. The calculations reveal that, in most cases, the O(S)∙∙∙H-O H-bonds are stronger than the O∙∙∙H-N ones. The calculated energies of highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) show that charge transfer occurs within the molecules.

In this research, the successful synthesis of spiro[acenaphthylene-1,9'-acridine] triones using 1,3-indandione, aniline and acenaphthoquinone in the presence of magnetic MnFe2O4@CS-Bu-SO3H NPs catalyst under ultrasonic irradiation in water is described. The catalyst was fully characterized by scanning electronic microscopy (SEM), vibrating sample magnetometer (VSM), X-ray diffraction (XRD), thermal gravimetric analysis (TGA), energy dispersive X-ray (EDX) and furrier transfer- infrared (FT-IR) spectroscopy. This method offers several advantages such as easy work-up, excellent yields, short reaction times, using of ultrasonic method, recoverability of the catalyst and little catalyst loading.

Nano-Zn-[2-boromophenyl-salicylaldimine-methylpyranopyrazole]Cl2 nanoparticles (nano-[Zn-2BSMP]Cl2) as a Schiff base complex and catalyst was used for the preparation of 2,4,5-tri substituted imidazoles by the one-pot multi-component condensation reaction of benzil with various aromatic aldehydes and ammonium acetate at 80 °C under solvent-free conditions.the formula is not displayed correctly!

A green and mild synthetic route to the convenient preparation of polyfunctionalized piperidines have been developed using ascorbic acid as a green and biodegradable catalyst via Knoevenagel- intramolecular [4+2] aza-Diels-Alder imin-based reaction in ethanol media. All reactions are completed by a five-component condensation reaction between 1,3-dicarbonyl compounds, aromatic aldehydes and various amines in short period of times and the products are obtained in good to high yields. The salient features of this environmentally friendly approach are green, biodegradable and readily available catalyst, straightforward work-up with no column chromatographic separation, mild reaction conditions, high atom-economy, avoidance of toxic organic solvents and highly efficient.

An easy and rapid method for the synthesis of bis-thiazolidinones has been presented by one-pot pseudo-five-component reaction of benzaldehydes, ethylenediamine, 2-mercaptoacetic acid with bis (1(3-trimethoxysilylpropyl)-3-methyl-imidazolium) nickel tetrachloride tethered to colloidal silica nanoparticles. Atom economy, low catalyst loading, reusable catalyst, applicability to a wide range of substrates and high yields of products are some of the important features of this protocol.

Reaction of 1,3-cyclohexanedione, aldehydes, and cyanogen bromide leads to the selective formation of octahydro-1H-xanthene-1,8(2H)-diones in moderate to good yields at room temperature under basic condition. The reaction of dialdehydes such as phthalaldehyde and terphthalaldehyde gaves tetrahydrodibenzo[b,e]oxepin-1(2H)-one and bifunctiolalized linked bis-xanthen analogues, respectively. All structures were characterized by FT IR, 1H and 13C NMR spectroscopy and Mass analysis techniques. The structure of 3c was analyzed by X-ray crystallography. The pKa and hydrogen bond strength (EHB) were determined in results of ≈11.7 and to ≈5 kcal.mol-1, respectively, via d(O•••••O) distance.

A novel ionic liquid entitled 3-methyl-1-sulfonic acid imidazolium mesylate ([Msim][OMs]) was synthesized, and characterized by studying its FT-IR, 1H NMR, 13C NMR and mass spectra. This ionic liquid was employed as a dual-functional catalyst for the preparation of bis-coumarins via the one-pot pseudo three-component reaction of 4-hydroxycoumarin (2 eq.) and arylaldehydes (1 eq.) under solvent-free and relatively mild conditions. Owing to dual-functionality of [Msim][OMs] (having acidic and basic sites), it could act as a highly effective catalyst for the reaction. Additionally, an attractive mechanism based on dual-functionality of the catalyst was proposed.

Herein,we propose a very simple,useful method for naming aldoses,ketoses (Fischer projection,cyclic structures),drawing their structures from their names with the aid of binary,decimal numbers. Fischer projections can be converted simply to the corresponding cyclic,Haworth forms,vice versa. Also one can easily find the R or S descriptors of any chiral center with the aid of a given binary number,without going through with the priority of its attached groups and,draw the enantiomer of any given monosaccharide.

In this study, a highly efficient and recyclable Brønsted acid ionic liquid, 1-methyl-3-(3-triethoxysilylpropyl)-1H-imidazol-3-ium hydrogensulfate, immobilized on the surface of Fe3O4@SiO2 (MNP-IL-HSO4) was prepared and characterized. Then, the catalytic activity of this nanomagnetic catalyst was investigated in the Friedländer synthesis of substituted quinolines through the cyclocondensation reaction of o-aminoaryl ketones with α-methylene carbonyl compounds under solvent-free conditions. The present protocol has several advantages, including short reaction times, high yield of products, simplicity in operation, simple work-up and reusability of the catalyst.