Sodium periodate-silica

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

Keywords oxime, sodium periodate, silica, microwave irradiation, ketone... 

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... 

Formerly derived from the natural mineral lapis lazuli, ultramarine blue pigments have, for more than a century, been manufactured synthetically. The materials used in the manufacture of ultramarines are china clay (a hydrated aluminosilicate), sodium carbonate, silica, sulfur and a carbonaceous reducing material such as coal tar pitch. For the manufacture of the blue pigments, the blend of ingredients is heated to a temperature of 750 800 °C over a period of 50-100 h, and the reaction... 

A facile deoximation procedure with sodium periodate impregnated on moist silica (Scheme 6.11) has also been introduced that is applicable exclusively to ketoximes [50], Aldehydes have been regenerated from the corresponding bisulfites (85-98%) on KSF clay surface [51]. 

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. 

Photolysis of J gives an isomeric compound K in 83% yield. Alkaline hydrolysis of K affords a hydroxy carboxylic acid L, C25H32O4. Treatment of K with silica gel in hexane yields M, C24H2g02. M is converted by sodium periodate-potassium permanganate to a mixture of N and O. What are the structures of K, L, and M ... 

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. 

The sulfide 1 (0.75 mmol) is dissolved in dichloromethane (2-3 mL) and adsorbed over silica supported sodium periodate (20%, 1.36 g, 1.28 mmol) that is wetted with 0.3 mL of water by thoroughly mixing on a vortex mixture. The adsorbed powdered material is transferred to a glass test tube and is inserted in an alumina bath (alumina 100 g, mesh 65-325, Fisher scientific bath 5.7 cm diameter) inside the microwave oven. The compound is irradiated for the time specified in the table and the completion of the reaction is monitored by TLC examination. After completion of the reaction, the product is extracted into ethyl acetate (2x15 mL). The removal of solvent at reduced pressure affords crude sulfoxide 2 that contains less than 5% sulfone. The final purification is achieved by column chromatography over silica gel column or a simple crystallization. 

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]. 

To a solution of tetrahydroxylamine in dichloromethane (300 mL) was added a solution of sodium periodate (2.45 g, 11.5 mmol) in water (500 mL) and the mixture was stirred for 1 h in the open air. The organic layer was separated, washed with water, dried over magnesium sulfate and concentrated. Purification was performed by column chromatography [silica, hexane-Et20 (1 1—0 1)] followed by GPC and then recrystallized from CH2Cl2-hcxanc by a diffusion method in the dark. Compound 10a was obtained as a dark-blue microcrystalline solid... 

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. 

The Step 7 product (113 mmol) dissolved in 600 ml dioxane was treated with 200 ml water and 4 ml 4% aqueous solution of osmium tetroxide, then stirred 5 minutes, and treated with sodium periodate (469 mmol). The mixture was heated 3 hours at 35°C, then cooled to ambient temperature, and diluted with 11 EtOAc. The solution was then washed with water, dried, and concentrated. The residue was recrystallized using THF and 15 g of product was isolated. The remaining filtrate was purified by chromatography with silica gel and EtOAc/hexanes, 1 1, so that a total product yield of 44% was observed. 

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. ... 

Silica gel OF 264 thin layer plate has been used with developing solvent of methanol - chloroform (1 3 ) to detect lincomycin (26). Lincomycin has an Rf of 0.65 detected by charring, iodine vapors, or permanganate spray. The latter consists of 10 gm of potassium carbonate, 8 gm of sodium periodate, and 1 gm of potassium permanganate in 500 ml of water. The mixture was left standing for 16 hours and filtered. 

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