Terpolymerization of Triisopropylsilyl Acrylate,Methyl Methacrylate,and Butyl Acrylate: Reactivity Ratio Estimation

Ternary monomer reactivity ratios of triisopropylsilyl acrylate (SiA), methyl methacrylate (MMA), and n‐butyl acrylate (BA), as common monomers in self‐polishing coatings (SPCs) binders are obtained using experimental data collected from free radical bulk polymerization at 70 °C. Different terpolymerizations at low and medium‐high conversions are performed at optimized feed compositions. Estimations are made using the error‐in‐variables model (EVM) framework, applying the recast form of the Alfrey–Goldfinger (AG) model and a direct numerical integration (DNI) approach to the collected data. Estimations from individual low and medium‐high conversion data are compared to those found with the combined data (full conversion range data). The highest certainty in point estimates are obtained with analysis of the full conversion range data. Furthermore, the reactivity ratios determined from the combined data fall between those found with analysis of individual low and medium‐high conversion data, another corroboration of reliable data collection. Reactivity ratios determined from analysis of the combined data (r_SiA/MMA = 0.4185, r_MMA/SiA = 1.3754, r_SiA/BA = 0.8739, r_BA/SiA = 0.5736, r_BA/MMA = 0.3692, r_MMA/BA = 1.7919) are used in the recast AG model to predict cumulative terpolymer composition as a function of conversion. The experimental data and model prediction show satisfactory agreement.     

β-Cyclodextrin-grafted magnetic graphene oxide nanocomposites in ultrasound-assisted dispersive magnetic solid-phase extraction for simultaneous preconcentration of lead and cadmium ions

Research on Chemical Intermediates - This article presents an ultrasound-assisted dispersive magnetic solid-phase extraction method (USA-DMSPE) to preconcentration Cd(II) and Pb(II) simultaneously....     

One-pot synthesis of novel polysubstituted furopyran derivatives via pseudo seven-component reaction (6 + 1) of isocyanides with bisarylidene Meldrum's acid containing ether groups

In the present study, a group of polysubstituted furopyran derivatives possessing ether spacer groups were synthesized under good-to-exceptional yields via cycloaddition of bisarylidene Meldrum's acid derivatives (1 mmol) with isocyanides (6 mmol) within dichloromethane (CH₂Cl₂) for 3 to6 hours at room temperature with no assistance from any type of catalysts. The structure of the products was then confirmed by Fourier Transform-infrared spectroscopy, ¹H-nuclear magnetic resonance spectroscopy, ¹³C-nuclear magnetic resonance spectroscopy, and elemental analysis. Moreover, the 5c , 5d , and 5f compounds exhibited favorable pharmaceutical behavior as antibacterial.     

Solubility of Acetaminophen and Ibuprofen in Polyethylene Glycol 600, N-Methyl Pyrrolidone and Water Mixtures

The solubility of acetaminophen and ibuprofen in binary and ternary mixtures of N-methyl pyrrolidone, polyethylene glycol 600 and water at 25 °C were determined and the solubilities are mathematically represented by the Jouyban–Acree model. The density of the solute-free solvent mixtures was measured and employed to train the Jouyban–Acree model and then the densities of the saturated solutions were predicted. The overall mean relative deviations (OMRDs) for fitting the solubility data of acetaminophen and ibuprofen in binary mixtures are 3.2% and 6.0%, respectively. The OMRDs for fitting the solubilities in ternary solvent mixtures for acetaminophen and ibuprofen are 15.0% and 28.6%, respectively, and the OMRD values for predicting all solubilities of acetaminophen and ibuprofen by a trained version of the Jouyban–Acree model are 9.4% and 17.8%, respectively. The prediction OMRD for the density of saturated solutions is 1.9%.     

Synthesis,anticancer, and computational studies of 1, 3, 4-oxadiazole-purine derivatives

Theophylline-7-acetic acid (acefylline) ( 3 ) and its derivatives are pharmacologically active compounds and generally recognized as bronchodilators for the treatment of respiratory diseases like acute asthma for over 70 years. In this article, synthesis of 2-((5-((1,3-dimethyl-2,6-dioxo-2,3-dihydro-1H-purin-7(6H)-yl)methyl)-1,3,4-oxadiazol-2-yl)thio)-N-arylacetamides ( 10a-j ) has been reported. All the synthesized derivatives ( 10a-j) were structurally verified by FT-IR, ¹H NMR, ¹³C NMR and evaluated for their anti-cancer (using MTT assay), hemolytic and thrombolytic potential. N-(4-Chlorophenyl)-2-(5-((1,3-dimethyl-2,6-dioxo-2,3-dihydro-1H-purin-7(6H)-yl)methyl)-1,3,4-oxadiazol-2-ylthio)acetamide ( 10g ) was found to be the most active against human liver cancer cell lines (Huh7) having cell viability 53.58 ± 1.28 using 100 μg/mL concentration of compound which was further in-silico modelled to describe the possible mechanistic insights for its anti-proliferative activity. The results of hemolytic and thrombolytic activities indicated that these derivatives were less toxic and hold considerable potential as a drug candidate. 2-(5-((1,3-Dimethyl-2,6-dioxo-2,3-dihydro-1H-purin-7(6H)-yl)methyl)-1,3,4-oxadiazol-2-ylthio)-N-(2-fluorophenyl)acetamide ( 10c ) of the series was found to be least toxic with 0.1% hemolysis relative to ABTS (95.5%) as positive control. 2-(5-((1,3-Dimethyl-2,6-dioxo-2,3-dihydro-1H-purin-7(6H)-yl)methyl)-1,3,4-oxadiazol-2-ylthio)-N-(tetrahydro-2H-pyran-4-yl)acetamide ( 10j ) exhibited potent clot lysis activity (90%) as compared to negative control DMSO (0.57%).     

Purification and Characterization of Pepsin-Solubilized Collagen from Skin of Sea Cucumber Holothuria parva

Pepsin-solubilized collagen (PSC) was extracted from the skin of sea cucumber Holothuria parva and was fractionally characterized. The PSC from H. parva skin consisted of three α₁ chains (α₁)₃, in contrast to calf skin collagen type I with two α₁ and one α₂ chains (α₁)₂α₂ with approximately 130 kDa each. The maximum transition (T_m) and denaturation temperature (T_d) of PSC were determined to be 46.94 and 32.5 °C, respectively. The amino acid composition analysis revealed that glycine, proline, alanine, and hydroxyproline were the abundant amino acids available in extracted PSC. The results showed that the isolated collagen from H. parva has some similar characteristics to previously reported collagens used in food and pharmaceutical industries.     

Silica aerogel–iron oxide nanocomposites: recoverable catalysts for the oxidation of alcohols with hydrogen peroxide

Various aerogels of silica gel doped with Fe₂O₃ were prepared by sol–gel method. They were calcined to produce nanoparticle solids. The nanosized mixed oxides were active in the oxidation of alcohols and produced carbonyl compounds in very good to excellent yields using hydrogen peroxide.     

Spectrophotometric Study of Complexation of Tri-Aza Dibenzosulfide and Dibenzosulfoxide Macrocyclic Compounds with Heavy Metal Ions

The complexation reactions between 7,10,13-triaza-1-thia-4,16-dioxa-20,24-dimethyl-2,3;17,18-dibenzo-cyclooctadecane-6,14-dione ( TTD ) and 7,10,13-triaza-1-sulfoxo-4,16-dioxa-20,24-dimethyl-2,3;17,18-dibenzo-cyclooctadecane-6,14-dione ( TSD ) macrocycles with Ag⁺, Cd²⁺, Cu²⁺, Pb²⁺, Sr²⁺, Tl⁺, and Zn²⁺ ions have been studied in ethanol and methanol solutions at 25°C. The complexes formed between macrocycles ( TTD ) and ( TSD ) with these metals cations had a stiochiometry of 1:1 and 1:2, respectively. The stability constants of the resulting complexes were determined and found to decrease in the order Cu²⁺ > Zn²⁺ > Ag⁺ > Tl⁺ > Cd²⁺ > Pb²⁺ > Sr²⁺ with macrocycle ( TTD ) and Tl⁺ > Zn²⁺ > Cd²⁺ > Pb²⁺ > Cu²⁺ > Ag⁺ > Sr²⁺ with macrocycle ( TSD ).     

Solubility Data of Diazepam in Binary and Ternary Mixtures of PEGs 200 and 400 with N-Methyl Pyrrolidone and Water at 298.2 K: Experimental Data and Modeling

Experimental solubilities of diazepam in binary and ternary solvents of polyethylene glycols 200 and 400 with N-methyl pyrrolidone and water at T = 298.2 K are reported. The Jouyban–Acree model was used to fit solubility data of diazepam in the binary and ternary solvent mixtures (106 data points) in which the overall mean relative deviations (OMRD %) is 13.1 % and the prediction OMRD % is 31.7 %. The combined version of the Jouyban–Acree model with Hansen solubility parameters was used for fitting and predicting the solubility data and the OMRDs % are 10.0 and 20.8 %, respectively. Also, the previously proposed trained versions of the Jouyban–Acree model were used for predicting the reported data in this work and all results are listed in the tables. The density of the solute-free solvent mixtures were measured and employed to calculate the constants of the Jouyban–Acree model and then the densities of the saturated solutions were predicted.     

Enantiopure Aminopyrans by a Lewis Acid Promoted Rearrangement of 1,2‐Oxazines: Versatile Building Blocks for Oligosaccharide and Sugar Amino Acid Mimetics

1,3‐Dioxolanyl‐substituted 1,2‐oxazines, such as syn‐ 1 and anti‐ 1 , rearrange under Lewis acidic conditions to provide bicyclic products 2 – 5 . Subsequent reductive transformations afforded enantiopure 3‐aminopyran derivatives such as 7 and 9 or their protected diastereomers 16 and 18 , which can be regarded as carbohydrate mimetics. An alternative sequence of transformations including selective oxidation of the primary hydroxyl groups in 21 and 24 led to two protected β‐amino acid derivatives with carbohydrate‐like backbone (sugar amino acids). Treatment of bicyclic ester 23 with samarium diiodide cleaved the N? O bond and furnished the unusual β‐lactam 27 in excellent yield. Alternatively, γ‐amino acid derivative 29 was efficiently prepared in a few steps. Fairly simple transformations gave azides 32 and 35 or alkyne 30 which are suitable substrates for the construction of oligosaccharide mimetics such as 34 by copper iodide catalyzed cycloadditions. With this report we demonstrate that enantiopure rearrangement products 2 – 5 are protected precursors of a variety of polyfunctionalized pyran derivatives with great potential for chemical biology.