Oxidation sodium periodate-silica

Oxidation of Sulfides to Sulfoxides and Sulfones - Sodium Periodate-Silica... 

Scheme 6 Solvent-free oxidation of sulfides using sodium periodate-silica [49]...

Chloro-2-(3-methyl-4H-1,2,4-triazol-4-yDbenzophenone (Oxidation of 7solution prepared by adding sodium periodate (2 g) to a stirred suspension of ruthenium dioxide (200 mg) in water (35 ml). The mixture became dark. Additional sodium periodate 18 g) was added during the next 15 minutes. The ice-bath was removed and the mixture was stirred for 45 minutes. Additional sodium periodate (4 g) was added and the mixture was stirred at ambient temperature for 18 hours and filtered. The solid was washed with acetone and the combined filtrate was concentrated in vacuo. The residue was suspended in water and extracted with methylene chloride. The extract was dried over anhydrous potassium carbonate and concentrated. The residue was chromatographed on silica... 

The oxidation of sulfides to the corresponding sulfoxides and sulfones proceeds under rather strenuous conditions requiring strong oxidants such as nitric acid, hydrogen peroxide, chromic acid, peracids, and periodate. Using MW irradiation, this oxidation is achievable under solvent-free conditions and with desired selectivity to either sulfoxides or sulfones using 10% sodium periodate on silica (Scheme 6.34)... 

Rj = PhCH2 R2 = Ph Rj = Ph, n-C12ttz R2 = Me Scheme 6.34 Oxidation of sulfides to sulfoxides and sulfones by silica-supported sodium periodate. 

Treatment of 53 with DAST [(diethylamino)sulfur trifluoride] in methylene chloride provided 57 in 50% yield. Compound 57 was treated with osmium tetroxide at 5 °C in the presence of NMO (4-methylmopholine N-oxide) for 18 h to provide 58 and 59, which were separated by silica-gel chromatography. Compounds 58 and 59 were treated with sodium periodate at 5 °C for 18 h to provide 60 and 61 respectively. Compounds 60 and 61 were treated with CDsMgl followed by NaB CN to give 62 in 20% and 50% yields, respectively. 

Selective oxidation of sulfides to sulfoxides and sulfones was achieved over sodium periodate (NaI04) on silica (20%), under solvent-free conditions to afford either sulfoxides or sulfones as desired (Scheme 5) [49]. 

Bis[3-methoxyphenyl] Tellurium Oxide1 0.80 g (2.3 mmol) of bis[3-methoxyphenyl] tellurium and 0.50 g (2.3 mmol) of sodium periodate are added to 30 ml of acctonitrilc/methanol/water (1/1/1, v/v/v) and the mixture is heated under reflux for 2 h. The mixture is allowed to cool, 100 ml of water are added, and the mixture is extracted 3 times with 30 ml of chloroform. The combined extracts are evaporated, the residue is chromatographed on silica gel with chloroform/methanol (9/1, v/v) as the mobile phase. The eluate is evaporated and the residue is recrystallized from benzene yield 0.26 g (22%) m.p. 189-191°. According to elemental analyses, the product contains two molecules of water and 1.5 molecules of benzene per molecule of tellurium oxide. 

Methods of oxidation of hydrazo to azo compounds and hydroxylamino to nitroso compounds have been reviewed. Reagents which oxidize aromatic primary amines to azo compounds are also suitable for the oxidation of aromatic hydrazo compounds, since the hydrazo compounds are intermediates in the oxidation of the amines. Thus, manganese dioxide, mercury(II) oxide and lead tetraacetate are all suitable oxidants. Silver carbonate on Celite rapidly oxidizes both diarylhydrazines and acylhydrazines to the corresponding azo compounds in good yield. Another supported oxidant which can convert hy-drazobenzene into azobenzene in high yield is sodium periodate on silica gel. ... 

On the other hand, the addition of sodium periodate supported on silica gel, which had been previously used for the oxidation of quinols to quinones, to 6-methoxybenzofuran-5-ol derivative (12) in dichloromethane promotes a single-electron oxidation process which leads to a stable semiquinone radical (13) instead of the expected o-quinone (eq 39). Other oxidants including AgO, CAN, DDQ, or nonsupported NalOa give complex mixtures of compounds. 

Sodium periodate supported on wet silica gel can be used for the conversion of ketoximes to the corresponding ketones under microwave irradiation. The reaction needs 2 equiv of the oxidant and less than 2 min to be complete (eq 43) on the other hand, the alternative heating protocol affords the products after 36 h at 110°C. 

Sodium periodate I silica Aldehydes from glycols Oxidative cleavage under mild conditions... 

Cui H, Park J-H, Park J-G. Effect of oxidizers on chemical mechanical planarization of ruthenium with colloidal silica based slurry. ECS J Solid State Sci 7ecfeioZ2013 2(l) P26—30. Cui H, Park J-H, Park J-G. Corrosion inhibitors in sodium periodate slurry for chemical mechanical planarization of ruthenium film. ECS J Solid State Sci Technol 2013 2(3) P71-5. 

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