With OXONE

Tlie reaction of 5,6-dithiabicyclo[2.1.1]hexaiie 11a with OXONE led to the corresponding dithiirane 12a, which was, however, stable only in solution (Amax at 442 nm in CH2CI2). Treatment of the reaction mixture containing 12a with MCPBA gave the dithiirane 1-oxide 13a (8%) (95TL1867). Tire introduction of electron-withdrawing substituents on the benzene rings provided the dithiirane oxide 13b in a better yield (21%). 

Tire reaction of 1,3-dithietanes 14 with OXONE produced dithiirane 1-oxides 15 directly (95TL1867). Dithiirane 1-oxides 15 would be formed through the initially formed 1,3-dithietane oxides. 

Treatment of ethyl 10-methylthio-9-fluoro-3-methyl-2,3-dihydro-7-oxo-7//-pyrido[l,2,3- 7e]-l,4-benzoxazine-6-carboxylate with oxone in aqueous MeOH at 0°C afforded 10-methylsulfonyl derivative (99H(51)1563). Methylthio group in a 7-(4-methylthiophenyl)-5-oxo-2,3-dihydro-5//-pyrido[l,2,3- 7e]-l,4-benzoxazine-3-carboxamide was oxidized to a sulfoxide and a sulfone group (OOMIPl). 

To mimic the square-pyramidal coordination of iron bleomycin, a series of iron (Il)complexes with pyridine-containing macrocycles 4 was synthesized and used for the epoxidation of alkenes with H2O2 (Scheme 4) [35]. These macrocycles bear an aminopropyl pendant arm and in presence of poorly coordinating acids like triflic acid a reversible dissociation of the arm is possible and the catalytic active species is formed. These complexes perform well in alkene epoxidations (66-89% yield with 90-98% selectivity in 5 min at room temperature). Furthermore, recyclable terpyridines 5 lead to highly active Fe -complexes, which show good to excellent results (up to 96% yield) for the epoxidation with oxone at room temperature (Scheme 4) [36]. 

Epoxidation of cyclooctene and other alkenes with Oxone (KHSO5) was promoted effectively in an aqueous micellar solution of an amphiphilic ketone (3.3).52 The amphiphilic ketone can be easily derived from hepta(ethylene glycol) monodecyl ether. 

The group of Botta demonstrated the feasibility of their microwave-assisted iodi-nation protocol (see Scheme 6.143 d) toward a polymer-supported substrate [68], An appropriate pyrimidinone attached to conventional Merrifield polystyrene resin was suspended in N,N-dimethylformamide, treated with 2 equivalents of N-iodosuccini-mide (NIS), and subjected to microwave irradiation for 3 min. Treatment of the polymer-bound intermediate with OXONE released the desired 5-iodouracil in almost quantitative yield (Scheme 7.57). 

Oxidation of the dithiabicyclo[3.3.1]heptane with Oxone leads to a mixture of the cis-and trans-1,2, 4,5-tetrathianes the former exists in a twist 103 and the latter in a chair 104 conformation <00BCJ729>. 

It is noteworthy that quick and effective formation of diaryl nitrones can be achieved through oxidation of diaryl imines with Oxone (potassium peroxy-monosulfate) in such media as aqueous solution of NaHCC>3 in acetonitrile or acetone. When oxidized under such conditions, dialkyl or monoaryl imines give oxaziridines (17). Oxidation of 3,4-dihydroisoquinoline (9) with Oxone initially leads to the formation of oxaziridine (10) which is easily transformed into the corresponding 3,4-dihydroisoquinoline A-oxide (11) upon treatment with catalytic amounts of p-toluenesulfonic acid (Scheme 2.4) (18). 

Oxidation of sulphides to sulphones with Oxone (Table 10.21)... 

Oxidation of 3,6-diamino-1,2,4,5-tetrazine (198) with oxone in the presence of hydrogen peroxide yields 3,6-diamino-l,2,4,5-tetrazine-2,4-dioxide (201) (LAX-112). The same reaction with 90 % hydrogen peroxide in trifluoroacetic acid yields 3-amino-6-nitro-1,2,4,5-tetrazine-2,4-dioxide (202). Treatment of 3,6-diamino-1,2,4,5-tetrazine (198) with 2,2,2-trinitroethanol and 2,2-dinitro-2-fluoroethanol generates the Mannich condensation products (203) and (204) respectively. 

Asymmetric epoxidation of olefins is an effective approach for the synthesis of enan-tiomerically enriched epoxides. A variety of efficient methods have been developed [1, 2], including Sharpless epoxidation of allylic alcohols [3, 4], metal-catalyzed epoxidation of unfunctionalized olefins [5-10], and nucleophilic epoxidation of electron-deficient olefins [11-14], Dioxiranes and oxazirdinium salts have been proven to be effective oxidation reagents [15-21], Chiral dioxiranes [22-28] and oxaziridinium salts [19] generated in situ with Oxone from ketones and iminium salts, respectively, have been extensively investigated in numerous laboratories and have been shown to be useful toward the asymmetric epoxidation of alkenes. In these epoxidation reactions, only a catalytic amount of ketone or iminium salt is required since they are regenerated upon epoxidation of alkenes (Scheme 1). 

In 2001, Yang and coworkers studied the use of in situ generated acyclic iminium salts as epoxidation catalysts [159]. Epoxidations of a number of aUcenes proceed with 20-50 mol% of amine 85 and aldehyde 86 with Oxone as the primary oxidant (Fig. 28.) Methylstilbene can be obtained in 100% conversion and 59% ee. 

Several efficient procedures for alkene epoxidation using Oxone were reported, such as Oxone/aqueous NaOH, Oxone/acetone, Oxone/water , Oxone/PTC/benzene/ aqueous buffer solution or Oxone/2-butanone system. Thus, sorbic acid can be regioselectively oxidized using Oxone/aqueous NaOH to 4,5-epoxy-2-hexenoic acid in 84% yield. Similarly, cyclooctene is oxidized to cyclooctene oxide in 81% yield, just by stirring it with Oxone in water . 1-Dodecene is epoxidized in good yield by Oxone/PTC in benzene aqueous buffer solution. It is otherwise difficult to epoxidize 1-dodecene by other oxidizing reagents. ... 

Recently, Crousse and coworkers reported that new fluoro ketones serve as efficient catalysts for the epoxidation reactions with Oxone in hexafluoropropan-2-ol (HFIP) (equation 46). ... 

Previously, some fluorocyclohexanones were used in a catalytic amount with Oxone for asymmetric epoxidation reaction, but they gave a poor ee . It was found later that chiral ketones derived from fructose work well as asymmetric epoxidation catalysts and show high enantioselectivity in reactions of /rani-disubstituted and trisubsti-tuted olefins ". Cis and terminal olefins show low ee under these reaction conditions. Interestingly, the catalytic efficiency was enhanced dramatically upon raising the pH. Another asymmetric epoxidation was also reported using Oxone with keto bile acids. ... 

Recently, Borhan and coworkers reported the facile oxidation of aliphatic and aromatic aldehydes to acids and esters in DMF or methanol with Oxone (equation 53) . These reactions are considered to be valuable alternatives to traditional metal-mediated oxidations. 

Sato and coworkers reported recently an interesting oxidation reaction of 1,4-dihydro-l,4-diphenyl-2,3-benzodithiin . When compound 38 was treated with m-CPBA in CH2CI2, ring contraction to l,3-diphenylbenzo[c]thiophene 39 was observed. With H2O2 in CH3COOH, the reaction afforded l,3-dihydro-l,3-diphenylbenzo[c]thiophene 40, while with Oxone a highly regioselective oxidized product, i.e. l,4-dihydro-l,4-diphenyl-2,3-benzodithiin 2,2-dioxide 41, was formed (equation 58). 

Selenides were oxidized with Oxone in buffered methanol to the corresponding selenones in quantitative yields . Webb and Levy showed that several boronic acids and boronic esters can be converted into the corresponding alcohols in excellent yields (equation 60). Oxone had been shown to be a better alternative than alkaline H2O2, which had been used... 

Aliphatic primary amines are known to be oxidized by dimethyl dioxiranes to various products such as oximes, nitroso dimers, nitroalkanes, nitrones and oxazrridines under various conditions depending upon the oxidation reaction . In contrast, when secondary amines lacking a-hydrogens are allowed to react with Oxone and PTC in buffered acetone solution at 0 °C, nitroxides are obtained in good yields in a few minutes (equation 61) . 

A new method for conversion of oximes to the corresponding em-halonitro derivatives using NaCl or KBr with Oxone and wet basic alumina was reported (equation 64) °. When the reaction was carried out under the same conditions but by using wet neutral alumina, complex mixtures of compounds in which the parent ketone is the most abundant product (>50%), due to the oxidative deprotection of the oxime, was obtained. 

Regeneration of ketones from tosylhydrazones with Oxone in acetone has been reported. Under controlled pH (pH = 6) the reaction gave very high yield (90%) of the product. In this paper we demonstrated that the use of in situ formed dimethyldioxirane under controlled pH conditions gives better results (equation 66). 

When a variety of aldehydes and Af,Af-dimethylhydrazones are treated with Oxone on wet AI2O3 under microwave irradiation in the absence of a solvent, the corresponding nitriles are obtained in good yields. Under these reaction conditions high selectivity... 

Primary, secondary and tertiary thioamides and thionreas are readily converted to their corresponding 0x0 analogs with Oxone in refinxing CH3CN . Thiono esters were converted to esters, while thioketones remained intact nnder these reaction conditions. Hydrazines can be selectively converted to esters and acids in high yields by nsing Oxone in an alcohol and a water, respectively . However, Mane and coworkers showed that hydrazides can be smoothly converted into the corresponding Af,Af -diacylhydrazines in excellent yields with Oxone in water (equation 67) . ... 

Methylisothiazolo[5,4- ]pyridin-3-(2//)-one-l-oxide 103 was quantitatively obtained by treating 104 with chlorine in aqueous acetic acid (Equation 13). The oxidation of 104 with Oxone at 60 °C in aqueous methanol gave 2-methylisothiazolo[5,4- ]pyndin-3-(2//)-one 1,1-dioxide 105 in a single step (Equation 14). No C-halogenation or N-oxidation products were detected under these reaction conditions <1996T8947>. 

Chiral ketone-catalyzed asymmetric epoxidation has received intensive interest since the first reported by Curci et al. in 1984. The reaction is performed with oxone (potassium peroxomonosulfate) as the primary oxidant which generates the chiral dioxirane catalytic species in situ, which in turn, transfers the oxygen... 

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