Preparation of a dual-functionalized fumed silica nanoparticle catalysis for synthesis of azaluorenone derivatives

Research on Chemical Intermediates - A dual-functional silica-based catalyst was prepared by treating fumed silica with amino-containing silane then 1,4-butane sultone. The presence of functional...     

The effect of cyclodextrin mixtures on aqueous solubility of beclomethasone dipropionate

The aim of present study was to evaluate the effect of natural, synthetic cyclodextrins (CDs) and CD mixtures on aqueous solubility of beclomethasone dipropionate (BDP). The phase solubility studies were done in the presence of 6 CDs. Furthermore, aqueous solubility of BDP was tested in the presence of CD mixtures. The solubility of BDP in water was increased by 30, 77, 155 and 30 folds in the solution containing 20%?w/v α-CD, hydroxylpropyl β-CD (HP-β-CD), hydroxypropyl γ-CD (HP-γ-CD) and sulphobutylether β-CD (SBE-β-CD), respectively. CD mixtures had remarkable effect on the aqueous solubility of BDP so that solubility in water increased between 200 and 1,500 times in the presence of different CD mixtures. Further addition of sodium acetate to the solubilisation medium reduced the aqueous solubility. In conclusion, CD complexation was able to improve the aqueous solubility of BDP. The synergistic effect of cyclodextrin mixture was observed.     

Application of SiO2-Pr-SO3H as an efficient catalyst in the Ritter reaction

Sulfonic-acid-functionalized silica was applied as an efficient heterogeneous acid catalyst in the Ritter reaction to prepare amides by reaction of various benzylic, allylic, and tertiary alcohols with various nitriles in good to excellent yields under solvent-free conditions. The simplicity of the reaction, recovery of catalyst without loss of reactivity, high yield of products, and short reaction time represent improvements over many existing methods.     

Application of SBA-Pr-SO<Subscript>3</Subscript>H in the synthesis of 2,3-dihydroquinazoline-4(1<Emphasis Type="Italic">H</Emphasis>)-ones: characterization,UV–Vis investigations and DFT studies

An efficient one-pot synthesis of 2,3-dihydroquinazoline-4(1H)-one derivatives 4a–l is described using SBA-Pr-SO₃H as a heterogeneous acid catalyst. The present methodology resulted in various derivatives of 2,3-dihydroquinazoline-4(1H)-one in good yield via a three-component reaction of isatoic anhydride, aldehydes and ammonium acetate. SBA-Pr-SO₃H played a significant role as an efficient mesoporous catalyst due to its pore size of 6 nm. Additionally, UV–Vis spectrum of the products was studied in order to investigate their application as UV absorbers.     

Highly efficient protection of alcohols as trityl ethers under solvent-free conditions,and recovery catalyzed by reusable nanoporous MCM-41-SO3H

An efficient method was developed for the protection of alcohols as trityl ethers using triphenylmethanol in the presence of nanoporous MCM-41-SO₃H as a heterogeneous catalyst under solvent-free ball-milling at room temperature. Low catalyst loading, high efficiency, reusability are among the advantages of this new solvent-free and environmentally friendly method. The deprotection of the produced trityl ethers was also efficiently achieved using the same catalyst in wet acetonitrile.     

The role of pyruvic acid as starting material in some organic reactions in the presence of SBA-Pr-SO<Subscript>3</Subscript>H nanocatalyst

Pyruvic acid contains three different reactive positions: –COOH, ketone carbonyl and methyl groups. Correspondingly, pyruvic acid was applied as starting material in the modified Niementowski reaction and Aldol condensation using SBA-Pr-SO₃H as an efficient nanocatalyst. Aldol condensation of pyruvic acid and oxindole provided a new oxindol-based carboxylic acid which was subsequently used in the Ugi four-component reaction. Moreover, through the modified Niementowski reaction of pyruvic acid, new derivatives of quiazoline were produced in the presence of SBA-Pr-SO₃H. The obtained products are important due to their potentially biological active skeletons.     

Cadmium electrodeposition on copper substrate for cyclotron production of <Superscript>111</Superscript>In radionuclide

^natCd electrodeposition on a copper substrate was investigated for production of ¹¹¹In radionuclide. The electrodeposition experiments were carried out by alkaline plating baths. Operating parameters such as pH, temperature, and current density are also optimized. The current efficiency was measured at different current densities. The optimum conditions of the cadmium electrodeposition were as follows: 2.35 g L⁻¹ cadmium, pH = 13, DC current density of ca 4.27 mA cm⁻² at 25 °C temperature with 62.48 μm thickness. SEM photomicrographs demonstrated fine-grained structure of the deposit obtained from the optimum bath.     

The molecular diversity scope of 4-hydroxycoumarin in the synthesis of heterocyclic compounds via multicomponent reactions

Molecular Diversity - 4-Hydroxycoumarins are some of the most versatile heterocyclic scaffolds and are frequently applied in the synthesis of various organic compounds. 4-Hydroxycoumarin-based...     

Evaluation the effect of cyclodextrin complexation on aqueous solubility of fluorometholone to achieve ophthalmic solution

In this study, the effect of different CDs including α-CD, β-CD, γ-CD, hydroxypropyl β-CD (HP β-CD), sulphobutylether β-CD (SBE β-CD) and HP γ-CD on aqueous solubility of fluorometholone (Flu) was investigated. Also the phase solubility studies were performed in the presence of eye drop excipients such as benzalkonium chloride, hydroxypropyl methylcellulose (HPMC) and buffers. The aqueous solubility of Flu was increased by 8, 15, 5, 100, 65 and 135 folds in the presence of 20% w/v α-CD, β-CD, γ-CD, HP β-CD, HP γ-CD and SBE β-CD, respectively. Aqueous solubility of Flu was 0.43 ± 0.08 and 1.16 ± 0.04 mg/mL in systems containing 5% w/v HP γ-CD and SBE β-CD, respectively. The aqueous solubility of Flu in the presence of HP γ-CD was not influenced by buffer type while the phosphate buffer caused a reduction in the aqueous solubility in the presence of SBE-β-CD. Also, investigations on the solubility of Flu in water in the presence of 5% HP γ-CD and SBE-β-CD and the additives such as benzalkonium chloride and HPMC indicated that these components had no remarkable effect on the aqueous solubility of Flu. In conclusion, CD complexation is able to improve the aqueous solubility of Flu and it would be possible to prepare ophthalmic solution of Flu by this method.     

Recent advances in asymmetric multicomponent reactions (AMCRs)

Asymmetric multicomponent reactions (AMCRs) include the reaction of three or more reactants simultaneously to produce chiral products that they have some advantages containing simple procedures, saving time and energy, and being environmentally friendly processes. AMCRs have seen much development and their potent synthetic approaches are discussed in this review.