The Characteristics of Direct Hydroxylation of Benzene to Phenol with Molecular Oxygen Enhanced by Pulse DC Corona at Atmospheric Pressure

The direct hydroxylation of benzene using molecular oxygen by atmospheric pulse DC corona discharge was investigated. The conversion of benzene increased with the increase of oxygen content and input voltage but the selectivity of phenol decreased due to the formation of polymerized products. The reactivity was also influenced by the kind and content of background inert gas. By using argon as background gas, we could get 2.2% of phenol yield at 60°C and 1 atm with energy consumption of 50 W. The strategy of reductive oxidation, which added hydrogen to the reactant, was not favorable to the phenol formation in this reaction system. The polymerized product showed the oligomeric character and the analysis of its chemical structure with FT–IR was presented.     

Vanadium Oxide: From Gels to Nanotubes

Vanadium oxide nanotubes (VO _x -NT) have been prepared by mixing hexadecylamine with V₂O₅·nH₂O gels. This procedure was followed by an hydrothermal treatment (150–180°C, 2–7 days) which leads to a large quantity of VO _x -NT. SEM and XRD analysis have been used to optimize the temperature and reaction time required for production of VO _x -Nt and morphology of the nanotubes investigated by TEM.     

Synthesis ad Some Conversions of Partially Hydrogenated 1-Aminopyrano(thiopyrano)[4,3-d]pyrazolo[3,4-b]pyridines and Pyrazolo[3,4-c]isoquinolines

We have synthesized derivatives of pyrano(thiopyrano)[4,3-d]pyrazolo[3,4-b]pyridine and pyrazolo[3,4-c]isoquinoline, and we have also carried out some conversions with them.     

Novel Stereoselective Synthesis of (E)- α，β-Unsaturated Esters by the Tandem Reaction of Deprotonation-Oxidation-Wittig Reaction from Phosphonium and Arsonium Salt

Phosphonium or arsonium salt 1 can undergo the tandem reaction of deprotonation -oxidation-Wittig reaction with alcohol 2 in the presence of sodium hydroxide and manganese dioxide,which affords a general simplified method for the stereoselective synthesis of (E)- α-β-unsaturated esters 3.     

Synthesis of novel dendrimers containing pyrimidine units

A novel convergent approach to dendritic macromolecules is described in which 4,6-dichloro-2-(4-methoxyphenyl)-pyrimidine is used as the building block. The nucleophilic aromatic substitution reaction at this AB₂-monomer was used as the key step in the propagation of the dendrons. Different core reagents were used to form the dendrimers, including a 5,15-bis(pyrimidyl)porphyrin core. Fourth-generation dendrons and third-generation dendrimers could be synthesized. The presented dendrimers are promising candidates to be used in applications where a more rigid structure and a larger resistance towards the applied conditions is required.     

A simple and easy access to 3-N-alkyl-5-vinyloxazolidinones mediated by palladium-phosphine catalysts

A new entry for the synthesis of 3-alkyl substituted 5-vinyloxazolidin-2-one derivatives 2 from cis-2-butenylene-1,4-dicarbonate 1 and primary amines mediated by palladium-phosphine catalysts is described. The scope and limitation, a plausible mechanism, and an asymmetric version of the reaction are also discussed.