A one-pot synthesis 3-alkoxycarbonyl-3,4-dihydro-2H-pyran-2-ones from vinylidene melderum's acids, dialkyl acetylenedicarboxylates, and simple alcohols.

A one-pot synthesis of 3-alkoxycarbonyl-3,4-dihydro-2H-pyran-2-ones from intermolecular hetero-Diels-Alder reaction between vinylidene Melderum's acids and dialkyl acetylenedicarboxylates, in the presence of simple alcohols at room temperature, is described. The advantages of this procedure are good yields, short reaction time, and easy workup. Antioxidant properties of four derivatives of these 3,4-dihydro-2H-pyran-2-ones, together with their antimicrobial activities, are investigated.

Solvent-free synthesis of new spiropyrroloindole compounds using Fe3O4/TiO2/MWCNTs MNCs via multicomponent reactions: assessment of new spiropyrroloindole antioxidant activity.

In this study, water extract of Spinacia oleracea leaves was used for the synthesis of Fe3O4/TiO2/MWCNTs magnetic nanocomposites and high performance of this catalyst was confirmed by employing it in the solvent-free multicomponent reactions of anilines, oxalyl chloride, diamines or hydroxyamines, electron-deficient acetylenic ester, α-haloketones and Et3N at room temperature for the generation of new spiropyrroloindoles in high yields. This catalyst could be utilized several times and has a significant role in the yield of product. The synthesized spiropyrroloindoles have NH and OH group in their structure and for this reason have good antioxidant activity. Also, by employing Gram-positive and Gram-negative bacteria and the disk diffusion procedure confirmed the antimicrobial effect of some spiropyrroloindole derivatives. The results showed that synthesized spiropyrroloindoles prevented the bacterial growth. This used process for preparation of new spiropyrroloindoles has some improvements such as low reaction time, product with high yields, and simple separation of catalyst and products.

Exploration of interaction behavior between spiro[indene-2,2'-[1,3,5]oxathiazine]-1,3-diones and DNA with the help of DFT, molecular docking, and MD simulations.

A detailed computational study covering density functional theory (DFT), molecular docking, and molecular dynamics (MD) simulations of some spirocyclic compounds interacting with a B-DNA has been performed. DFT calculations were performed using the B3LYP functional with 6-311++G(d,p) basis set and were used to identify the electrophilic and nucleophilic centers in electrostatic forces. NMR results were in agreement with previous experimental data and approved the reliability of the used method and basis set. The in silico screening results showed that spirocyclic compounds fulfill the Lipinski's rule of five and can be developed as potential oral bioavailable drug candidates. Based on molecular docking results, the binding affinities follow the 4c < 4d < 4a = 4b < 4e < 4g < 4f order and ranged from -8.6 to -9.7 kcal/mol indicating a reasonably favorable interaction between DNA and investigated compounds. The adducts were stabilized by hydrophobic and hydrogen bonding interactions. The MD simulations performed for 100 ns and the results are reported in terms of variables such as root-mean-square deviation (RMSD), root-mean-square fluctuation (RMSF), center of mass (COM) separation distance between DNA and ligands, intermolecular hydrogen bonds, and radial distribution functions (RDF). The MD simulations demonstrated that compounds 4a and 4d bind into the minor groove of 1BNA and may act as potential biological probes for B-DNA.Communicated by Ramaswamy H. Sarma.

Synthesis of Novel α-amidino Carboxylic Acids and their Use as H-Bond Catalysts in Strecker Reaction.

AIM AND OBJECTIVE: A wide variety of synthesized amidine derivatives are bioactive compounds. They show a vast range of medical properties. Therefore, a simple route for synthesis of novel class of amidine derivatives called amidino carboxylic acids and their use as catalysts in Strecker reaction has been reported in the current work. The stability, local charge density and hydrogen bond parameters were calculated for eight derivatives with different substituents. MATERIALS AND METHODS: In order to synthesize these amidino carboxylic acids, we initially prepared Knovenogel condensation products via the reaction of isatin derivatives with malonitrile. When the reaction was performed in water, the resulting nitrile groups of malonitrile derivatives was hydrolyzed with HOAC/ H2SO4 to generate the desired amide groups. The amide groups in resulting compound converted to amine groups with two Hoffman rearrangements in the presence of NaOH/Br2. Further neutralization led to the final zwitterionic α-amidino carboxylic acids. In the next step, the catalytic activity of these compounds as H-bond donor catalyst was investigated in Strecker reaction. RESULTS: The overall yields of the derivatives with substituent on the aromatic ring of starting isatins are higher than that for the overall yields of nitrogen-substituted isatins. The reaction of 5-nitro isatin with the next reagent gives lower yield in aryl-substituted products. An increase of catalytic activity is observed by rising the electron-withdrawing power of the aromatic ring substituents., The presence of nitro group in the structure of catalyst caused a large increase of catalytic activity in Strecker reaction. DFT calculations at B3LYP/6-31++g(d,p) and Lanl2dz level of theory showed that these compounds act as single H-bond catalysts and higher yields were obtained for complexes with stronger hydrogen bond. CONCLUSION: A simple and efficient method for synthesis of ɑ-amidino carboxylic acids was developed in this research. These compounds have been used as a single H-bond donor catalyst in the Strecker reaction. DFT calculations were carried out to confirm the experimental results. The obtained data from computations are in good agreement with experimental results.

Synthesis and characterization of carboxymethyl chitosan/Fe3O4 and MnFe2O4 nanocomposites hydrogels for loading and release of curcumin.

This paper presents the preparation of hydrogel with magnetic properties derived from carboxymethyl chitosan for controlled drug release performance. The magnetic Fe3O4 and MnFe2O4 nanoparticles with crosslinked Carboxymethyl Chitosan hydrogel were prepared by using epichlorohydrin as the cross-linker. The structure characterization performed by FT-IR. The XRD analysis was applied for evaluation of crystalline phase of MnFe2O4 and Fe3O4 in the hydrogels. The crystallite size of Fe3O4/CMCS and MnFe2O4/CMCS was calculated to be 30.12, and 44.51 nm, respectively. The presence of MnFe2O4 and Fe3O4 in the hydrogels can reason a rough surface morphology which that confirmed by SEM images. The Max. Saturation magnetization value as obtained from hysteresis loop is 105 and 75 Am2/kg for Fe3O4/CMCS and MnFe2O4/CMCS hydrogel, respectively. The Fe3O4 and MnFe2O4 on Carboxymethyl Chitosan hydrogels indicated a pH-sensitive for swelling behavior process. The equal amount of Fe3O4 and MnFe2O4 on hydrogels have high swelling at pH 6.4. The swelling capacity decreased from 214 to 172% and 144-114% at pH 6.4 with attendance of high amount of MnFe2O4 and Fe3O4 on hydrogels compared to other samples, respectively. Drug loading and release performances were investigated by curcumin as a model drug. The maximum curcumin release was obtained 25.1-51.52% at pH = 6.4. The drug releases system demonstrates the high ratio of Fe3O4 and MnFe2O4 containing Carboxymethyl Chitosan sample has a great efficiency in curcumin release. The effect of applied magnetic field on drug release for Fe3O4/CMCS was highest compared to MnFe2O4/CMCS. The results demonstrated that the Fe3O4 and MnFe2O4 nanocomposites hydrogel can be applied for novel drug delivery systems.

H2TPP organocatalysis in mild and highly regioselective ring opening of epoxides to halo alcohols by means of halogen elements.

We found that elemental iodine and bromine are converted to trihalide nucleophiles (triiodine and tribromide anion, respectively) in the presence of catalytic amounts of meso-tetraphenylporphyrins (H2TPP). Therefore a highly regioselective method for the synthesis of beta-haloalcohols through direct ring opening of epoxides with elemental iodine and bromine in the presence of H2TPPs as new catalysts is described. At room temperature a series of epoxide derivatives were converted into the corresponding halohydrins resulting from an attack of trihalide species anion atoms at the less substituted carbon atom. This method occurs under neutral and mild conditions with high yields in various aprotic solvents, even when sensitive functional groups are present.

Functionalization of carboxylated multiwall nanotubes with imidazole derivatives and their toxicity investigations.

Imidazoles and their derivatives are compounds with chemotherapeutic applications. In this study, we investigated the chemical functionalization of carboxylated multiwalled carbon nanotubes (MWNT-COOH) by 1,2-phenylendiamine. Multiwalled nanotube (MWNT)-benzimidazole was obtained by an MWNT-amide reaction with POCl(3) after 72 hours, which was confirmed by Fourier transform infrared, scanning electron microscopy, thermal gravimetric analysis, and elemental analysis. These functionalizations were chosen due to -NH(2) and NHCO active sites in MWNT-amide for future application. Toxicity assays with fibroblast cells and MTT test for measurement of viable cell numbers were also performed. Cellular results did not show any toxicity change in modified samples from that of the reference samples.

Microwave-assisted solvent-free synthesis of Bis(dihydropyrimidinone)benzenes and evaluation of their cytotoxic activity.

An effective one-pot synthesis of bis(dihydropyrimidinonoe)benzenes using chlorotrimethylsilane (TMSCl) through Biginelli condensation reaction of terephthalic aldehyde, 1,3-dicarbonyl compounds and (thio)urea or guanidine under microwave irradiation conditions is described. Excellent yields of the products and simple work-up are attractive features of this green protocol. Then, the cytotoxic activities of these compounds were evaluated on five different human cancerous cell lines (Raji, HeLa, LS-180, SKOV-3 and MCF7). Their cytotoxic study indicated that they possessed a weak to moderate activity. Furthermore, the higher activity of compound 4b bearing sulfur in C2 position of pyrimidinone ring showed the importance of this site for cytotoxic activity of these compounds.

Electrochemical synthesis of 4-(dihydroxyphenylthio)-2H-chromen-2-one derivatives.

The 4-(dihydroxyphenylthio)-2H-chromen-2-one derivatives have been synthesized by direct electrochemical oxidation of catechols in the presence of 4-mercaptocoumarin as a nucleophile in water/acetonitrile (50/50) solution, in a one-pot process, at carbon rod electrode, in an undivided cell and in constant current conditions, through an EC mechanism. The products are characterized by spectra data. Besides, the difference in electrochemical oxidation of catechol in the presence of 4-hydroxycoumarin and 4-mercaptocoumarin explained by computational structure, natural bond orbital (NBO) analysis and density functional theory (DFT: B3LYP/6-31G*//B3LYP/6-31G*) based methods, using the GAUSSIAN 98 package of programs.

A novel one-pot synthesis of some new interesting pyrrole derivatives.

[reaction: see text] 11-(1H-Pyrrol-1-yl)-11H-indeno[1,2-b]quinoxaline and 3-(1H-pyrrol-1-yl)indolin-2-one derivatives have been synthesized in good yields in a novel, one-pot, and efficient process by condensation of 11H-indeno[1,2-b]quinoxalin-11-one or isatin derivatives with 4-hydroxyproline on solid-support montmorillonite K10 under microwave irradiation.

A stereoselective three-component reaction: KAl(SO4)2.12H2O, an efficient and reusable catalyst for the one-pot synthesis of cis-isoquinolonic acids.

KAl(SO(4))(2).12H(2)O is found to catalyze efficiently the stereoselective one-pot three-component cyclocondensation of homophthalic anhydride, aldehydes, and amines under mild conditions to afford the corresponding cis-isoquinolonic acids in good yields.

A novel one-pot, four component synthesis of some densely functionalized pyrroles.

A new one-pot four component procedure for synthesis of densely functionalized pyrroles using commercially available ninhydrin with phosphorane intermediates produced in the reaction between triphenylphosphine, ammonium thiocyanate (or ammonium acetate) and various dialkyl acetylenedicarboxylates was developed.