Water promoted one-pot synthesis of 2′-aminobenzothiazolomethyl naphthols and 5-(2′-aminobenzothiazolomethyl)-6-hydroxyquinolines

A novel one-pot, three-component condensation reaction of an aldehyde, 2-aminobenzothiazole and 2-naphthol or 6-hydroxyquinoline in water to give 2′-aminobenzothiazolomethyl naphthols or 5-(2′-aminobenzothiazolomethyl)-6-hydroxyquinolines in high yields at 90 °C without using any catalyst, is described.     

Green Oxidations. Manganese(II) Sulfate Aided Oxidations of Organic Compounds by Potassium Permanganate

Summary. The oxidation of arenes and sulfides by potassium permanganate was accomplished in good yields under solvent free and heterogeneous conditions when manganese(II) sulfate is used as a solid support. After extraction of the organic products, the inorganic products can be reoxidized to permanganate. This result is important because it provides an approach to oxidation reactions that is, in theory, infinitely sustainable.     

One-step Synthesis of 3,4-Dihydrobenzimidazo[2,1- b ]quinazolin-1(2 H )-ones in an Ionic Liquid

A novel class of 3,4-dihydrobenzimidazo[2,1-b]quinazolin-1(2H)-ones was synthesized in very short reaction times with good yields in the presence of 3-butyl-1-methyl imidazolium bromide as a room temperature ionic liquid at 120°C. The ionic liquid can be recycled for subsequent reactions without any loss of efficiency.     

Synthesis of tetrahydrobenzimidazo[1,2-b]quinazolin-1(2H)-one and tetrahydro-1,2,4-triazolo[5,1-b]quinazolin-8(4H)-one ring systems under solvent-free conditions

Tetraheterocyclic benzimidazo[1,2-a]quinazolin-4(1H)-one and tetrahydro-1,2,4-triazolo[5,1-b]quinazolin-8(4H)-one were synthesized in relatively high yields by the condensation reaction of an aldehyde and a cyclic beta-diketone with 2-aminobenzothiazole, 2-aminobenzimidazole or 3-amino-1,2,4-triazole without using any catalyst under solvent-free conditions.     

Carbon Ceramic Electrodes Modified with Laccase from Trametes hirsuta: Fabrication,Characterization and Their Use for Phenolic Compounds Detection

Fungal laccase (Lc) from the basidiomycete Trametes hirsuta was immobilized on top of a carbon ceramic electrode using physical absorption. Direct, unmediated heterogeneous electron transfer between Lc and the carbon ceramic electrode (CCE) under aerobic conditions was shown. The bioelectrocatalytic reduction of oxygen on Lc‐CCE started at about 430 mV vs. Ag|AgCl|KCl_sat at pH 3.5 and moved with about 57 mV in the cathodic region per pH unit. The Lc‐modified CCE was then used as a biosensing detection element in a single line flow injection system for the amperometric determination of a variety of phenolic substrates of the enzyme. The experimental conditions were studied and optimized for catechol serving as a model compound. Statistical aspects were applied and the sensor characteristics and Michaelis‐Menten constants of the investigated phenolic compounds were calculated and compared with those obtained for solid graphite electrodes modified with Trametes hirsuta laccase. The results showed that the CCE based biosensor in comparison with the solid graphite based biosensor offers a lower detection limit, a wider linear dynamic range, and excellent operational stability with no sensor passivation, indicating that the sol–gel lattice improves the electrochemical behavior of the biosensor.     

A one-pot,three-component synthesis of spiro[indoline-isoxazolo[4′,3′:5,6]pyrido[2,3-d]pyrimidine]triones in water

A one-pot, three-component condensation reaction of an isatin, isoxazole, and barbituric acid in water to give spirooxindoles in high yields, at 70 °C temperature, using a catalytic amount of p-toluene sulfonic acid, is described.     

On the signed star domination number of regular multigraphs

Let $G$ be a graph with the vertex set $V(G)$ and the edge set $E(G)$ . A function $f: E(G)\longrightarrow \{-1, 1\}$ is said to be a signed star dominating function of $G$ if $\sum _{e \in E_G(v)}f (e)\ge 1 $ , for every $v \in V(G)$ , where $E_G(v) = \{uv\in E(G)\,|\,u \in V (G)\}$ . The minimum values of $\sum _{e \in E_G(v)}f (e)$ , taken over all signed star dominating functions $f$ on $G$ , is called the signed star domination number of $G$ and denoted by $\gamma _{SS}(G)$ . In this paper we determine the signed star domination number of regular multigraphs.     

An Easy One-Pot Procedure for the Synthesis of N -Sulfonyl Phosphorous Ylides and Sulfonyl Iminophosphoranes

Reaction of triphenylphosphine and an electron deficient acetylenic ester in the presence of strong N–H acid such as alkyl and aryl sulfamides or acetamide produces phosphorous ylides at room temperature in CH₂Cl₂. The aryl sulfamide phosphoranes undergo a smooth transformation reaction in boiling toluene and produce iminophosphoranes.     

Ionic liquid promoted selective oxidation of organic compounds with NaBrO3

1-Butyl-3-methylimidazolium bromide ([bmim]Br) as an ionic liquid promoted selectively the oxidation of alkyl arenes and alcohols to the corresponding carbonyl compounds with NaBrO₃ in excellent yields under neutral conditions at the 70°C. Among the various ionic liquids examined, the [bmim]Br exhibited the best performances with NaBrO₃. The ionic liquid can be recycled and reused for several runs without any significant loss of activity. Correspondence: Ahmad Shaabani, Department of Chemistry, Shahid Beheshti University, P.O. Box 19839-4716, Tehran, Iran.