Aromatization of Hantzsch 1,4‐Dihydropyridines in Solventless System Using Glycinium Chlorochromate

Glycinium chlorochromate (GCC) supported onto silica gel was used as an effective oxidizing agent for the aromatization of 1,4‐dihydropyridines to corresponding pyridine.     

KHSO4 Supported Onto Bentonite,A Versatile Reagent for Aromatization of Hantzsch 1,4‐Dihydropyridines

Aromatization of Hantzsch 1,4‐dihydropyridines was promoted by KHSO₄, a relatively green chemical, supported onto bentonite to yield the corresponding pyridine derivatives in excellent yields. The reaction was carried out under mild and convenient conditions.     

Aromatization of Hantzsch Ester 1,4‐Dihydropyridines with Iodine under Normal Conditions and Ultrasound Irradiation

A variety of Hantzsch ester 1,4‐dihydropyridines are efficiently oxidized to their corresponding pyridine compounds with iodine under normal conditions and ultrasound irradiation. The reactions were carried out in refluxing CH₃CN.     

Oxidative Aromatization of Hantzsch 1,4-Dihydropyridines Catalyzed by Ferric Perchlorate in Ionic Liquids with Air

A variety of Hantzsch 1,4-dihydropyridines were oxidized to the corresponding pyridines catalyzed by a catalytic amount of ferric perchlorate. The reaction was carried out in ionic liquid at room temperature, and the products were isolated in good to excellent yields. At the same time, the catalytic system was found to be reusable.     

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.     

A New Application of Hexamethylenetetramine‐Bromine Supported onto Wet Alumina as an Efficient Reagent for Cleavage of Phenylhydrazones under Classical Heating and Microwave Irradiation

2,4‐Dinitrophenylhydrazones were converted to their parent carbonyl compounds using hexamethylenetetramine‐bromine complex supported onto wet alumina under classical heating and microwave irradiation.     

Chromium Trioxide Supported onto Wet Silica Gel: Rapid Oxidation of Alcohols to Carbonyl Compounds Under Microwave Irradiation in Solventless System

In an environmentally benign system, alcohols are rapidly oxidized to carbonyl compounds using CrO 3 supported onto wet silica gel as an oxidant under microwave irradiation.     

Quinoxalinium Fluorochromate (QxFC): A New and Efficient Reagent for the Oxidation of Alcohols in Solution,Under Solvent-Free Conditions and Microwave Irradiation

The new mild oxidizing agent, quinoxalinium fluorochromate (QxFC), has been easily prepared by reacting quinoxaline with an aqueous solution of CrO ₃ and HF. This reagent is suitable for oxidizing various primary and secondary alcohols to their corresponding carbonyl compounds and anthracene to antraquinone. The reactions were carried out in solution, under solvent-free conditions and microwave irradiation. The results show that the rates of the reactions and the yields are usually highest under microwave irradiation.     

Affinity,Speciation, and Molecular Features of Copper(II) Complexes with a Prion Tetraoctarepeat Domain in Aqueous Solution: Insights into Old and New Results

Characterization of the copper(II) complexes formed with the tetraoctarepeat peptide at low and high metal‐to‐ligand ratios and in a large pH range, would provide a breakthrough in the interpretation of biological relevance of the different metal complexes of copper(II)‐tetraoctarepeat system. In the present work, the potentiometric, UV/Vis, circular dichroism (CD), and electron paramagnetic resonance (EPR) studies were carried out on copper(II) complexes with a PEG‐ylated derivative of the tetraoctarepeats peptide sequence (Ac‐PEG₂₇‐(PHGGGWGQ)₄‐NH₂) and the peptide Ac‐(PHGGGWGQ)₂‐NH₂. Conjugation of tetraoctarepeat peptide sequence with polyethyleneglycol improved the solubility of the copper(II) complexes. The results enable a straightforward explanation of the conflicting results originated from the underestimation of all metal–ligand equilibria and the ensuing speciation. A complete and reliable speciation is therefore obtained with the released affinity and binding details of the main complexes species formed in aqueous solution. The results contribute to clarify the discrepancies of several studies in which the authors ascribe the redox activity of copper(II)‐tetraoctarepeat system considering only the average effects of several coexisting species with very different stoichiometries and binding modes.