Synthesis of gold nanoparticles decorated on sulfonated three‐dimensional graphene nanocomposite and application as a highly efficient and recyclable heterogeneous catalyst for Ullmann homocoupling of aryl iodides and reduction of p‐nitrophenol

Gold nanoparticles were decorated onto sulfonated three‐dimensional graphene (3DG‐SO₃H) through spontaneous chemical reduction of HAuCl₄ by 3DG‐SO₃H. This nanocomposite exhibited excellent catalytic activity for the synthesis of symmetric biaryls via the Ullmann homocoupling of aryl iodides in an aqueous medium. Additionally, this nanocomposite was used as a catalyst for the reduction of p‐nitrophenol to p‐aminophenol. The catalyst could be used more than six times successively without significant deactivation.     

Synthesis and Characterization of Poly(Biphenyl‐2‐yl p‐Styrenesulphonate) as Profungicide in Controlled Release Technique

A new fungicide controlled release formulation was prepared by the reaction of p‐styrenesulphonyl chloride with biphenyl‐2‐ol (Dowicide A) as fungicide. The resulting monomer containing the fungicide was polymerized with benzoyl peroxide as initiator. The monomer and the polymer were identified by spectroscopic methods, and molecular weight of the polymer was determined by GPC. Also mp, Tg and Td of the polymer were identified by DSC. The release characteristic of the polymer was studied in neutral, alkaline, and acidic media. Also, the effect of the temperature on the release of bioactive agent (Dowicide A) was investigated. The hydrolysis data showed that the release rates are strongly dependent upon the pH of the medium and the temperature.     

A practical and versatile approach toward a one-pot synthesis of 2,3-disubstituted 4(3H)-quinazolinones

Abstract  

An effective one-pot three-component route to 4(3H)-quinazolinones from commercially available starting materials is reported. Thus, isatoic anhydride reacted with ammonium acetate or primary amines and aldehydes in the presence of iodine to produce the corresponding quinazolinone derivatives in moderate to good yields.     

Selective Method for the Conversion of Oximes to Their Corresponding Carbonyl Compounds under Microwave Irradiation by N‐Bromo‐N‐Phenyl‐Para‐Toluenesulfonamide

In this work, oximes are converted to their corresponding carbonyl compounds in good yields using N‐bromo‐N‐phenyl‐para‐toluenesulfonamide, under microwave irradiation. The simple work‐up procedure minimizes loss of product.     

Efficient synthesis of mono- and disubstituted 2,3-dihydroquinazolin-4(1H)-ones using KAl(SO4)2·12H2O as a reusable catalyst in water and ethanol

KAl(SO₄)₂·12H₂O was found to catalyze efficiently a one-pot three-component cyclocondensation of isatoic anhydride and primary amines or ammonia sources such as (NH₄)₂CO₃, NH₄OAc and NH₄Cl with aromatic aldehydes under mild conditions to afford the corresponding mono- and disubstituted 2,3-dihydroquinazolin-4(1H)-ones in good yields.     

Efficient One-Pot,Four-Component Synthesis of 1,2,3-Triazole-Linked Tetrahydrobenzo[b]pyrans

A one-pot procedure has been developed for the synthesis of (1,2,3-triazolyl) methoxyphenyl tetrahydro-5-oxo-4H-chromene derivatives by concurrent reaction of aryloxy propargylated aldehydes, various azides, active methylene compounds, and 1,3-cyclohexanediones using catalytic amounts of Cu(OAc)₂ / sodium ascorbate and diammonium hydrogen phosphate in aqueous ethanol media. Excellent conversion of starting materials was achieved to the desired (1,2,3-triazolyl) methoxyphenyl tetrahydro-5-oxo-4H-chromene products.     

Novel and efficient one-pot tandem synthesis of 2-styryl-substituted 4(3H)-quinazolinones

A novel one-pot tandem synthesis of 2-styryl-4(3 H)-quinazolinones in an acidic ionic liquid is reported. In this procedure isatoic anhydride, a primary aniline or ammonium acetate, and triethylorthoacetate are reacted in the presence of imidazolium trifluoroacetate [Hmim]TFA. Subsequently an aromatic aldehyde is added to the mixture to afford the title compounds in high to excellent yields.     

Crack Damage in Polymers and Composites: A Review

Polymer-based materials are extensively used in various applications such as aircrafts, civilian structures, oil and gas platforms and electronics. They are, however, inherently damage prone and over time, the formation of cracks and microscopic damages influences the thermo-mechanical and electrical properties, which eventually results in the total failure of the materials. This paper provides an overview of the principal causes of cracking in polymer and composites and summarizes the recent progress in the development of non-destructive techniques in crack detection. Furthermore, recent progress in the development of bio-inspired self-healing methods in autonomic repair is discussed.