Synthesis of Thio Analogues of Quinolone Antibacterials

A facile and rapid synthesis of thio compounds, analogues to ciprofloxacin, and norfloxacin is described.     

Fabrication and application of a new modified electrochemical sensor using nano-silica and a newly synthesized Schiff base for simultaneous determination of Cd,Cu and Hg ions in water and some foodstuff samples

A new chemically modified carbon paste electrode was constructed and used for rapid, simple, accurate, selective and highly sensitive simultaneous determination of cadmium, copper and mercury using square wave anodic stripping voltammetry (SWASV). The carbon paste electrode was modified by N,N′-bis(3-(2-thenylidenimino)propyl)piperazine coated silica nanoparticles. Compared with carbon paste electrode, the stripping peak currents had a significant increase at the modified electrode. Under the optimized conditions (deposition potential, −1.100 V vs. Ag/AgCl; deposition time, 60 s; resting time, 10 s; SW frequency, 25 Hz; pulse amplitude, 0.15 V; dc voltage step height, 4.4 mV), the detection limit was 0.3, 0.1 and 0.05 ng mL⁻¹ for the determination of Cd²⁺, Cu²⁺ and Hg²⁺, respectively. The complexation reaction of the ligand with several metal cations in methanol was studied and the stability constants of the complexes were obtained. The effects of different cations and anions on the simultaneous determination of metal ions were studied and it was found that the electrode is highly selective for the simultaneous determination of Cd²⁺, Cu²⁺ and Hg²⁺. Furthermore, the present method was applied to the determination of Cd²⁺, Cu²⁺ and Hg²⁺ in water and some foodstuff samples.     

Al(HSO4)3 and Al2O3-SO3H as Efficient Catalysts for Modified Preparation of 3,4-Dihydropyrimidin-2 (1H)-ones/thiones

An environmentally friendly procedure for the preparation of dihydropyrimidinone derivatives or their sulfur analogues under thermal solvent-free conditions in the presence of aluminium hydrogen sulfate [Al(HSO₄)₃] and alumina sulfuric acid (Al₂O₃-SO₃H) as heterogeneous catalysts was developed.     

Microwave-Assisted Synthesis of Quinoxalines,Benzoxazines, and Benzothiazines Under Solvent-Free Conditions

The addition of dialkyl acetylenedicarboxylate to o-phenylenediamine, o-aminophenol, and o-aminothiophenol under microwave irradiation in solventless system rapidly afforded quinoxaline, benzoxazine, and benzothiazine derivatives, respectively.     

Solvent Free Synthesis of Coumarins

An efficient synthesis of 3-substituted coumarins under solventless system is described.     

Microwave Thermolysis: A Rapid and Selective Method for the Cleavage of THP Ethers Using CrO 3 Supported onto Zeolite in Solventless System

Oxidative deprotection of tetrahydropyranyl ethers (THP ethers) using chromium trioxide supported onto zeolite under microwave irradiation in solvent free condition is described.     

Synthesis of Bicyclic Compounds Derived from 1,2,4-Benzotriazines

The synthesis of bicyclic compounds derived from benzo[1,2,4]triazines is described.     

Old Reagent,New Results: Aromatization of Hantzsch 1,4-Dihydropyridines with Supported Bismuth Nitrate under Microwave Irradiation in Solventless System

Hantzsch 1,4-dihydropyriines were rapidly and efficiently oxidized using bismuth nitrate supported onto silica gel under microwave irradiation.     

ZEOLITE-SUPPORTED CHROMIUM(VI) OXIDE: A MILD,EFFICIENT, AND INEXPENSIVE REAGENT FOR OXIDATIVE DEPROTECTION OF TRIMETHYLSILYL ETHERS UNDER MICROWAVE IRRADIATION

Primary and secondary trimethylsilyl ethers are effeciently converted to the corresponding carbonyl compounds using HZSM-5 zeolite-supported CrO ₃ under microwave irradiation in solventless system.     

FACILE REDUCTION OF AROMATIC NITRO COMPOUNDS WITH HYDROIODIC ACID UNDER MICROWAVE IRRADIATION ON SOLID SUPPORT

Reduction of aromatic nitro compounds to amine with hydroiodic acid was revisited. Under microwave irradiation on solid support the reduction proceeded efficiently and rapidly.