Green Method for the Synthesis of Benzo[f]pyrimido[4,5-b]quinoline Derivatives Catalyzed by Iodine in Aqueous Media

A convenient one-pot synthesis of benzo[f]pyrimido[4,5-b]quinoline derivatives is described via three-component reaction of benzaldehydes, naphthalen-2-amine, and barbituric acid at room temperature in aqueous media catalyzed by iodine. Compared with other methods, this three-component reaction used a green solvent, gave good yields, and was operationally simple.     

New Cytotoxic Triterpenoids from the Aerial Parts of Euphorbia sieboldiana

Phytochemical investigation of the EtOH extract of Euphorbia sieboldiana led to the isolation of four new oleanane‐type triterpenoids, (1β,2α,3β,19β)‐1,2,3,19‐tetrahydroxyolean‐12‐en‐28‐oic acid, (1β,3β,19β)‐1,3,19‐trihydroxyolean‐12‐en‐28‐oic acid, (1β,2α,3β,16β,19β)‐1,2,3,16,19‐pentahydroxyolean‐12‐en‐28‐oic acid, and (1β,2α,3β,19β,23)‐1,2,3,19,23‐pentahydroxyolean‐12‐en‐28‐oic acid, along with 16 known compounds. Their structures were established by extensive 1D‐ and 2D‐NMR, as well as other spectral analyses. Biological evaluation of the four new triterpenoids revealed potent cytotoxic activities against HeLa and Hep‐G2 cells.     

A study on the direct electrochemistry and electrocatalysis of microperoxidase-11 immobilized on a porous network-like gold film: Sensing of hydrogen peroxide

We have prepared porous and network-like nanofilms of gold by galvanic replacement of a layer of copper particles acting as a template. The films were first characterized by scanning electron microscopy and X-ray diffraction, and then modified with cysteamine so to enable the covalent immobilization of the enzyme microperoxidase-11. The immobilized enzyme undergoes direct electron transfer to the underlying electrodes, and the electrode displays high electrocatalytic activity towards the reduction of oxygen and hydrogen peroxide, respectively, owing to the largely enhanced electroactive surface of the porous gold film. The detection limit of H₂O₂ is 0.4 μM (3 S/N).

Surface active properties of N-(2-Aminoethyl)-3-aminopropyltetrasiloxane lactobionamide and aggregation behavior in aqueous solution

The aggregation behavior of tetrasiloxane-lactobionamide (Si4N2-LA) in aqueous solution has been characterized by dynamic light scattering (DLS), negative-stained transmission electron microscopy (TEM) and X-ray Diffraction methods. Compared with the micellar sizes 7.0 nm of n-dodecyllactobionamide (C12Glu2), the Si4N2-LA molecule can self-assemble into spherical vesicle with diameters in the range from 60 to 300 nm.     

Ammonium Chlorochromate Adsorbed on Silica Gel: A New Reagent for the Oxidation of Alcohols and Benzoins to Corresponding Carbonyl Compounds

A new reagent, Ammonium chlorochromate adsorbed on silica gel, suitable for the oxidation of alcohols and benzoins to the corresponding carbonyl compounds is described.     

New Synthetic Method of p-Nitrocalixarenes

Calixarenes 1 were directly nitrated with potassium nitrate and aluminum chloride to give p-nitrocalixarenes 2 in good yields. Formation of p-nitrocalix[4]arene (2a) from reaction of p-bromomethylcalix[4]arene (3) with silver nitrate is also described.     

Hydrogen Peroxide–Promoted Transformation of Thioureas/Thiosemicarbazides to Related Ureas/Semicarbazides at Room Temperature via Grinding

A novel and environmentally benign synthetic method for ureas through hydrogen peroxide–promoted desulfurization of thioureas at room tepemperature via grinding is reported. As compared with the traditional method, this one is manipulatively simple and the oxidant is low cost, highly active, and environmentally friendly.     

Prins Cyclization of Styrenes or Acetophenone Catalyzed by DBSA in Water

Dodecylbenzenesulfonic acid (DBSA) was proved to be an efficient catalyst for Prins cyclization of styrenes and formaldehyde or acetaldehyde in water. A tandem dehydration/Prins cyclization reaction using a tertiary alcohol and formaldehyde as substrates proceeded very well by using DBSA as catalyst. Acetophenone, which is less reactive compared with styrene, can also react with formaldehyde when catalyzed by DBSA in water to afford 1,3-dioxan-5-ylphenylmethanone in good yield.     

Cascade reaction for 3-pyrrolines and pyrroles from nitroallylic acetates and N-mesyl 2-aminoethanones

Cascade reactions of nitroallylic acetates with methanesulfonyl 2-aminoethanones affords either the 3-pyrrolines or the pyrroles in one pot depending on reaction solvents and temperature. A possible mechanism for the entire sequence is proposed.     

Synthesis of β,β′-edge fused, π-extended porphyrins and their applications in the dye-sensitized solar cells

Four π-extended, β,β′ aromatic ring fused porphyrins including mono- and opp-dibenzoporphyrins bearing two carboxyl groups at only one fused benzo group were synthesized. The optical results by UV–vis spectroscopy indicate that when compared with the absorption spectra of monobenzoporphyrins, greater light-harvesting capabilities can be realized for opp-dibenzoporphyrins with two benzo group at the opposite β,β′ positions of the porphyrin. The photovoltaic properties of these π-extended porphyrins were examined for the first time and the highest conversion efficiency of 1.62% was realized for opp-dibenzoporphyrin 8a-sensitized solar cell, which is ∼60% higher than that of monobenzoporphyrin 4a based solar cell indicating the effect of an extra aromatic π conjugation on the light-harvesting capabilities of π-extended porphyrins. Subsequent DFT calculation results supported our results obtained in the optical and photovoltaic studies.