Organic Chemistry Research
Volume:3 Issue: 2, Autumn 2017

A new efficient method for the synthesis of 2,3-dihydroquinazolin-4(1H)-ones and spiroquinazolinones via a condensation reaction of aldehydes and ketones with anthranilamide in the presence of nano Fe3O4@SiO2-SO3H as catalyst in ethanol has been described. The reactions are completed in short times, and the corresponding dihydroquinazolinones are produced with high yields. The present procedure has several advantages, including short reaction times, high yields of products, facile experiment, simple work-up, eco-friendly reaction conditions, and reusability of the catalyst. The catalyst could simply be separated and recovered by an external magnet and reused in subsequent reactions with no considerable loss in activity.

An easy method was developed for the efficient preparation of diversely new 5,5-disubstituted N(3),N'(3)-linkaged bis-hydantoins. At first, using the same methods, some ketones and terephthalaldehyde were converted to several hydantoins and a new bis-hydantoin , respectively. Then 1,6-dibromohexane, as a mild reagent, was employed for the alkylation and incorporation of synthesized substrates to produce quantitative yields of the desired bis-hydantoins. A tetrakis-hydantoin including four effective heterocyclic rings was also surprisingly synthesized from 5,5'-(1,4-phenylene)bis(imidazolidine-2,4-dione). The aim of this study is to synthesis of bis- and tetra core-hydantoins, bis-drug-like molecules employing a practical and reliable reaction process that requires slight amount of reagents; a process that is simple, accessible producing remarkable yields from an easy procedure that is cost effective and/or environmentally friendly. The resultant hydantoins potentially have bis- or multi-drugs behaviors in comparison with mono-counterparts, as cited in literatures for similar heterocyclic compounds. Spectral analysis confirmed the structures of the synthesized hydantoins.

Highly substituted piperidines were synthesized via the condensation of aromatic aldehydes and aromatic amines with β-ketoesters in the presence of antimony(III) chloride at ambient condition. This reaction has any advantages such as easy work-up, clean procedure, and good yields.

Some new compounds based on bis-benzimidazole moieties have been synthesized and characterized by IR and NMR spectroscopies. The ability of 3a in transition metal cation sensing such as Co2+, Ni2+, Zn2+, Mn2+, Fe2+ and Cu2+ have been investigated by Uv-vis and fluorescence spectroscopy in methanol solvent. The complexation constants and complex stoichiometry of Cu2+ have been determined. The experimental result show that 3a exhibits high selectivity toward Cu2+ cation in a 1:1 complex stoichiometry. The absorption bond and the fluorescence intensity have been increased by addition of successive amount of Cu2+ solution in methanol. Therefore, these results demonstrate that, the compound can be used as a sensor to detect Cu2+ cation via absorption and emission spectroscopy.

Some aryl and heteroaryl azido compounds were synthesized from the reaction of corresponding fluoro and chloro compounds with sodium azide in DMF as solvent and under various reaction conditions especially ultrasonic irradiation. Reaction of aromatic and heteroaromatic azido compound with thioacetic acid in the presence of sodium hydrogen carbonate and in methanol as solvent led to the different products. Further intermolecular nucleophilic aromatic substitution reaction of N-(perfluoropyridin4-yl)acetamid allow the regioselective synthesis of 2,6,7-trifluoro-2-methyloxazolo[4,5-c]pyridine. The structures of all compounds were confirmed by IR, 1H NMR and 13C NMR spectroscopy as well as elemental analysis

Stachys lavandulifolia is from mint family and Labiatae species and grows in different parts of our country sporadically. The purpose of this study is to investigate the chemical properties of Stachys lavandulifolia Ethyl acetate extract. In this study, the Ethyl acetate extract was provided using maceration method. The extract then was defatted and solvent removal performed in a subsequent process. Some tests such as Testing the ability of neutralizing free radicals, Measuring the total phenolic compounds using the Folin–Ciocalteu method were used. The Ethyl acetate extract was consequently IC50%= 53.60 , using Testing the ability of neutralizing free radicals method. The reducing percent was calculated in terms of Ethyl acetate concentration and compared with natural and synthetic antioxidant. The results showed that with increasing concentration, antioxidant activity will be increased.

Cellulose sulfuric acid is an efficient metal-free catalyst for the synthesis of 1,3,5-trisubstituted pyrazoles via the condensation of 1,3-diketones and hydrazines. The reaction was carried out in Solvent-free condition at room temperature and the products were isolated in good to excellent yields. Mild reaction conditions, as well as ease of operation and workup are some advantages of the proposed protocol.

In the present work, the substituent effect on the strength of H-bonds in the guanine – cytosine base pair was studied when the substituents are connected to the guanine base through a phenyl ring. In this study, guanine was substituted in the H8 and H9 positions by electron donating (ED) and electron withdrawing (EW) groups mediated by a phenyl ring in the gas phase. The calculations were performed at B3LYP/6-311++G(d,p) level. The results show that the values of stabilization energies (EHB) of EW groups are more negative than that of ED groups. These results indicate that the complexes containing EW groups are more stable than ED ones. Also, the energies of the intermolecular hydrogen bond have been estimated by the EML and MAEM’s formulas. Most of the changes of intermolecular hydrogen bond are agreement with the nature of substituents. The influence of substituent on the stability of complexes is investigated by atoms in molecules and natural bond orbital analyses. The atoms in molecules theory were also used to get the most exact understanding to the nature of H-bond interactions. There is excellent relationship between the charge distribution and the stabilization energy.

In this work, copper(II) heterogeneous nanocatalyst supported on modified AlPO4 (Cu(II)-DA@Nano AlPO4) was used for the synthesis of some biological active heterocyclic molecules, particularly for the efficient conversion of a wide range of non-activated terminal alkynes to β-hydroxy 1,4-disubstituted 1,2,3-triazolethrough a three-component “click” reaction at room temperature in water. The regioselective reactions exclusively gave the corresponding 1,4-disubstituted 1,2,3-triazoles in good to excellent yields. The Cu(II)-nanocatalyst has high catalytic activity, and was recycled ten successive times. This heterogeneous nanocatalyst not only offers substantial improvements in the reaction rates, but also avoids the use of hazardous catalysts, solvents and intermediates. Moreover, the reaction can be performed in large scale.

A practical and green synthesis of 3-substituted indoles is reported via three-component coupling reaction of indoles, aldehydes and N-methylaniline in the presence of the acidic ionic liquid 1-butyl-3-methylimidazolium hydrogen sulfate ([BMIm]HSO4) under ultrasound irradiation at room temperature. The significant features of this procedure are high yields of the products, simple work-up, operational simplicity and non-toxicity of the catalyst. Moreover, [BMIm]HSO4 is successfully reused for four cycles without significant less of activity. Keywords. Indoles, N-methylaniline, Aldehyde, Ionic liquid.

Novel pyrazole derivatives 2-7 are synthesized by the reaction of 2-substituted 1,3-bis(dimethylamino)-trimethinium salts with phenyl hydrazine in acetonitrile as the solvent. This method has some advantages of high yields (78-85%), simplicity of the process and easy of control. The ultraviolet spectral behavior of the synthesized compounds is examined in CDCl3 and their structures were characterized by elemental analysis, FTIR, 1H and 13C NMR and Mass spectra.

In the present work, we have reported the in situ oxidation of manganese (II) acetate to MnO2 nanoparticles through the thermal plasma carbonized natural hydroxyapatite (MnO2/TP-NHAp) as a neoteric sustainable method. Interestingly, the thermal plasma-processed surface of the NHAp shows a great ability for oxidation of the manganese (II) without need of any external oxidizing agents. The catalyst was characterized by X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), thermogravimetric analysis (TGA), flame atomic absorption spectroscopy (FAAS), Fourier transform infrared (FT-IR), scanning electronic microscopy (SEM), and energy dispersive spectroscopy (EDS). The catalytic activity of MnO2/TP-NHAp was investigated in the selective aerobic oxidation of alcohols and benzylic alkyl arenes at 80 °C in toluene under an atmospheric pressure of air as a source of oxidant. Since the catalyst can be easily recovered and reused at least for four consecutive cycles without losing significant activity and selectivity, it showed admirable potential in reusable catalysis.