Ruthenium dioxide-Sodium metaperiodate

Oxidation of cyclic amines. Sheehan and Tulis have examined the oxidation of acylated cychc amines with ruthenium tetroxide in a chlorinated solvent (single-phase system) or with ruthenium dioxide—sodium metaperiodate in CHCI3-H2O (two-phase system). Lactams can be obtained in good yield by oxidation of 1-methyloxalylpiperidine or l-methyloxalylpyrroUdine (1) with RUO4. Tlih, protective group is cleaved with sodium methoxide in methanol. The N-carboethoxy derivative of azetidine (n = 0) is oxidized in low yield... 

Rose Bengal, 431 Rosenmund reaction, 393 Ruthenium dioxide-Sodium metaperiodate, 504... 

Preparation of Ruthenium Tetroxide Solution. Ruthenium dioxide (0.4 g) is suspended in 50 ml carbon tetrachloride. A solution of 3.2 g sodium metaperiodate in 50 ml water is added and the mixture stirred 1 hr at 0°. The black ruthenium dioxide gradually dissolves. 

Preparation of Ruthenium Tetroxide (/5) In a 250-ml flask equipped with a magnetic stirrer and cooled in an ice-salt bath is placed a mixture of 0.4 g of ruthenium dioxide and 50 ml of carbon tetrachloride. A solution of 3.2 g of sodium metaperiodate in 50 ml of water is added and the mixture is stirred 1 hour at 0°. The black ruthenium dioxide gradually dissolves. The clear yellow carbon tetrachloride layer is separated and filtered through glass wool to remove insoluble materials. The solution may be used immediately or stored in the cold in the presence of 50 ml of sodium metaperiodate solution (1 g/50 ml). As prepared above, the solution is about 0.037 M in ruthenium tetroxide and contains 0.3 g/50 ml. 

Mild allylic oxidation of the A-2-crotyl-substituted thiadiazolidinone 1,1-dioxide 140 by sodium metaperiodate/ ruthenium trichloride hydrate (RuC13) gave the aldehyde 141. Excess oxidizing agent afforded the carboxylic acid 142 (Equation 26) <1999EJ02275>. 

While there is ample room for debate at the theoretical level, the importance of this straightforward route to compound 20 could hardly be missed. Attention could now be directed to the necessary functional group adjustments. Reduction of the ester (lithium triethoxyborohydride) followed by benzoylation (benzoyl chloride, DMAP) afforded an 80% yield of 22. Treatment of this compound with ruthenium dioxide in the presence of sodium metaperiodate, followed by diazomethane, provided ester 23 in 90% yield. 

Ruthenium tetroxide, generated in situ from a suspension of the dioxide in CCI4, by adding aqueous sodium metaperiodate, appears to be an excellent reagent for the oxidation of secondary alcohols in neutral or basic media. t-Amyl or cumyl hydroperoxide, with molybdenum pentachloride, readily oxidizes steroidal alcohols cholesterol affords the 5a-hydroxy-3,6-dione in good yield. ... 

However, oxidation of the 26-diethylaminoethylthio derivative of pristinamycin IIb (94a), or the corresponding sulfinyl analog (97), using ruthenium tetroxide generated in situ from a catalytic amount of ruthenium dioxide with sodium metaperiodate as the co-oxidant, afforded the desired 26-diethylamino-sulfonyl derivative (98) in good yield. Alternative ruthenium catalysts included ruthenium trichloride or tris(triphenylphosphine)ruthenium(II) chloride. 

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