M-Chloroperoxybenzoic acid

Oxidation oi S-fluoro-t,3-dimethyluraciI by m-chloroperoxybenzoic acid leads to 4-hydroxy-l,3-dimethylimidazoledione m-chlorobenzoate [80] (equadon 72). 

Fluoro-2,2-dinitroethylamine is oxidized by m-chloroperoxybenzoic acid 10 the corresponding hydroxylamine, which, on further oxidation by a second equivalent of the peroxyadd or bromine, gives an oxime [85] (equation 77)... 

Conjugated 1,3-diazadienes are oxidized by m-chloroperoxybenzoic acid to I-oxa-2,4-diazoles [SS] (equation 80)... 

Oxidation of more lipophihc pentafluorophenyl sulfamimine to the corresponding sulfamyloxaziridine by m-chloroperoxybenzoic acid gives better yields in a shorter tune compared with the nonfluonnated analogue [95] (equation 87)... 

Trifluoromethanesulfinyl chloride is prepared by oxidation of trifluorometh-anesulfenyl chloride with m chloroperoxybenzoic acid in high yield [110] (equa tion 101)... 

Perfluoro(tetramethylene) sulfiUmine is easily oxidized to a sulfoximme by m-chloroperoxybenzoic acid [773] (equation 103)... 

It is possible to introduce this group selectively onto a primary alcohol in the presence of a secondary alcohol. The derivative is stable to KMn04, m-chloroperoxybenzoic acid, LiAlH4, and Cr03-Pyr. Since this derivative is similar to the p-methoxyphenyl ether, it should also be possible to remove it oxidatively. The GUM ethers are less stable than the MEM ethers in acid, but have comparable stability to the SEM ethers. It is possible to remove the GUM ether in the presence of a MEM ether. 

In the laboratory, as we saw in Section 7.8, epoxides are prepared by treatment of an alkene with a peroxyacid (RC03H), typically m-chloroperoxybenzoic acid. 

Whenever a chiral product is formed by reaction between achiral reagents, the product is racemic that is, both enantiomers of the product are formed in equal amounts. The epoxidation reaction of geraniol with m-chloroperoxybenzoic acid, for instance, gives a racemic mixture of (2R,3S) and (2S,3R) epoxides. 

When the reagent is the thiocyanate ion, S-alkylation is an important side reaction (10-43), but the cyanate ion practically always gives exclusive N-alkylation. ° Primary alkyl halides have been converted to isocyanates by treatment with sodium nitrocyanamide (NaNCNN02) and m-chloroperoxybenzoic acid, followed by heating of the initially produced RN(N02)CN. ° When alkyl halides are treated with NCO in the presence of ethanol, carbamates can be prepared directly (see 16-7). ° Acyl halides give the corresponding acyl isocyanates and isothiocyanates. For the formation of isocyanides, see 10-111. 

Many other reagents for converting alkenes to epoxides,including H2O2 and Oxone , VO(0-isopropyl)3 in liquid C02, ° polymer-supported cobalt (II) acetate and 02, ° and dimethyl dioxirane.This reagent is rather versatile, and converts methylene oxiranes to spiro-epoxides. ° ° One problem with dimethyloxirane is C—H insertion reactions rather than epoxidation. Magnesium monoperoxyphthalate is commercially available, and has been shown to be a good substitute for m-chloroperoxybenzoic acid in a number of reactions. 

The epoxidation step can also be performed with m-chloroperoxybenzoic acid in CH2CI2. Reference(s) ... 

The silyl enol ethers of ketones are also oxidized to a-hydroxy ketones by m-chloroperoxybenzoic acid. If the reaction workup includes acylation, a-acyloxy ketones are obtained.250 These reactions proceed by initial epoxidation of the silyl enol ether, which then undergoes ring opening. Subsequent transfer of either the O-acyl or O- l MS substituent occurs, depending on the reaction conditions. 

Synthesis of Allylic Alcohol Xa. A 3.84 g sample of olefin VII was treated with m-chloroperoxybenzoic acid (MCPBA) in dichloromethane for 1.5 hours at 0°C and 2.5 hours at 20°C. The NMR spectrum of the crude product indicated a mixture of approximately 75% epoxide VIII and 25% IX (structural assignments based upon assumed epoxidation preferentially from the less hindered side). Purification by column chromatography furnished 0.61 g of IX and 2.58 g of VIII. The separation was performed for characterization purposes the crude epoxidation mixture was suitable for subsequent transformations. 

When 3 is treated with m-chloroperoxybenzoic acid oxidation at the ring nitrogen occurs (Scheme 2). Product 4 is a pale yellow viscous fluid which is soluble in organic solvents but immiscible with water having a partition ratio of 24 1 in a CH2CI2/H2O medium. The IR spectrum of 4 gives direct evidence for the presence of... 

Cyclohexene-1 -methanol undergoes smooth Williamson etherification with a,co-dibromoalkanes in the presence of base and a phase transfer catalyst. The resulting biscyclohexenyl ethers, XXIIa-e, were subsequently treated with m-chloroperoxybenzoic acid to give the desired diepoxide monomers, XXIIIa-e. Table 3 gives the characteristics of these monomers. 

In miscellaneous oxidative processes of indoles, two methods for the preparation of 3-hydroxyindoles have been reported. The first approach involves initial Vilsmeier-Haack reaction of indole-2-carboxylates 176 to afford the corresponding 3-formyl analogs 177. Activation of the aldehyde with p-toluenesulfonic acid (PTSA) and Baeyer-Villiger oxidation with m-chloroperoxybenzoic acid (wi-CPBA) then affords high yields of the 3-hydroxy compounds 178 <00TL8217>... 

Ethyl trifluoroacetate Acetic acid, trifluoro-, ethyl ester (8,9) (383-63-1) m-Chloroperoxybenzoic acid Peroxybenzoic acid, m-chloro- (8) Benzocarboperoxoic acid, 3-chloro- (9) (937-14-4)... 

Organolithium additions to 2-phenyl-3,3-dimethyl-3//-indole (37), followed by oxidation of indolines (38) with m-chloroperoxybenzoic acid, gave indolinic aminoxyls (39) in 20-30% yield. The organolithium addition does not occur when groups other than phenyl are present at C(2). Attempts to synthesize suitable precursors such as 1,2-dihydro-2-phenyl-2-alkylbenzothiazole, 1,2-dihydro-2-phenyl-2-alkylbenzoxazole, and l,2-dihydro-2-phenyl-2-alkyl-4//-3,l-benzoxazin-4-one for other new aminoxyls failed. 

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