Funding information Islamic Azad University-Arak BranchAn efficient method for the N-alkylation of poorly nucleophilic amines using ferric perchlorate immobilized on SiO 2 as a catalyst is described. Fe(ClO 4 ) 3 was prepared from mixing iron(III) hydroxide and perchloric acid and adsorbed on silica gel. The catalyst was characterized using various techniques. The supported ferric perchlorate (Fe(ClO 4 ) 3 /SiO 2 ) revealed high efficiency and selectivity for N-alkylation of aromatic amines with alcohols to provide alkylated amines. Various secondary amines were synthesized from primary amines and alcohols in good to excellent yields, with water as the only by-product. The optimization of the reaction conditions was investigated using the response surface method, and involving the Box-Behnken design matrix. The conditions for optimal reaction yield and time were: amount of catalyst = 0.34 mmol, temperature = 60°C and molar ratio of amine to alcohol = 1.2.The catalyst was recovered and reused for five cycles without a considerable decrease in catalytic activity. The stability of the recycled catalyst was investigated. The proposed method has numerous advantages including procedure simplicity, short reaction times, low cost, good to excellent yields, reusability of the catalyst and mild and environmentally benign conditions.

Irradiation of unsymmetrically substituted 1,4-dihydropyridines (1b-1j) while bubbling oxygen or argon through the solution resulted in aromatization to the corresponding pyridine derivatives (3b-3j). Compound 1a with 2-nitrophenyl substituent in 4-position undergoes elimination of water upon irradiation under both oxygen and argon atmospheres and formation of 3a with 2-nitrosophenyl substituent. On the other hand, irradiation of the compounds 1e, 1k and 1l with 4-hydroxy-3-methoxyphenyl, 5-methyl-2-furyl and 2-furyl substituent in this position, respectively, resulted in the expulsion of these substituents and formation of a pyridine derivative unsubstituted in position 4, namely compound 2. Chloroform as a solvent causes the photo-oxidation of these compounds by an electron transfer mechanism which is supported by the formation of dichloromethane according to GC analysis and presence of acid (HCl) in the solution after irradiation.

A novel magnetically separable natural acidic ionic liquid immobilized on magnetic silica were fabricated by covalent bonding of thiamine (VB1) modified with (3‐glycidyloxypropyl)trimethoxysilane (GMSI) moiety on the silica modified Fe3O4. The catalytic properties have been evaluated in one‐pot multi‐component synthesis of biscoumarins and substituted xanthene derivatives through the Domino Knoevenagel‐Michael reaction of a wide range of substrates under solvent free conditions. A variety of readily accessible aldehydes with different substituted functional groups have been converted to biscoumarins with good to excellent isolated yields and short reaction times. The novel nanocatalyst was characterized by infrared spectroscopy (FT‐IR), X‐ray diffraction (XRD), scanning electron microscopy (SEM/EDS) and thermogravimetric (TG) analysis. The catalyst was reused up to five consecutive cycles with high activity and selectivity and separated easily from the reaction mixture by an external magnetic field.

Photosensitized oxidation of unsymmetrically substituted 1,4-dihydropyridines using dye sensitizers methylene blue, rose bengal and tetraphenylporphyrin by taking visible light source resulted in the aromatization of dihydropyridine ring and formation of the corresponding pyridine derivatives. Comparison of the results obtained under photosensitized reaction with those obtained by direct photo-oxidation indicated a very fast and smooth reaction of these compounds and formation of pyridine derivatives using theses dyestuffs.

A practical and highly efficient silylation of alcohol and phenol derivatives with hexamethyldisilazane (HMDS) using acidic ionic liquids under mild reaction conditions is described. A series of Brønsted as well as Brønsted–Lewis acidic ionic liquids were prepared and their performance investigated for the silylation of a wide variety of alcohols and phenols with HMDS. Imidazole‐ as well as N‐methyl‐2‐pyrrolidone‐based acidic ionic liquids have a higher catalytic activity for the protection of sensitive, hindered alcohols and phenols, thus providing an environmentally begin and versatile alternative to current acid catalysts. In addition, the acidic ionic liquids are reusable, being recovered easily and reused several times without significant deterioration in catalytic activity.