Oxone-alumina

Other Metallic Oxidants - Copper Sulfate or Oxone-Alumina... 

A rapid microwave oxidation protocol for the oxidation of alcohol to carbonyl compound has been reported by Varma (2001). Different types of oxidizing reagents have been used with microwave irradiations. Alcohols were converted into corresponding carbonyl compounds in the presence of montmorillonite KIO clay-sup-ported iron (111) nitrate (Clayfen), Oxone-alumina, IBD-alumina, 35% MnO doped silica, CrO,-alumina or CuSO-alumina under microwave irradiation and solvent-free conditions in few minutes (0.25-3.5 min). 

Cl2, ammonium nitrate on Clayfen, Oxone on wet alumina, silver nitrate and iodine,2,3-dichloro-5,6-dicyano -1,4-benzoquinone (DDQ) in acetonitrile... 

The regeneration of carbonyl compounds from 1,3-dithianes can be achieved using potassium hydrogen persulfate, Oxone , supported on wet alumina <96SL767> and by periodic acid under non-aqueous conditions <96TL4331>. The deprotection of benzyl substituted 1,3-dithianes can be achieved using the one electron oxidant [Fe(phen)3](PF6)3 <96SL315>. 

Symmetrical and unsymmetrical benzoins have been rapidly oxidized to benzils in high yields using solid reagent systems, copper(II) sulfate-alumina [105] or Oxone-wet alumina [105, 106] under the influence of microwaves (Scheme 6.32). Conventionally, the oxidative transformation of a-hydroxy ketones to 1,2-diketones is accomplished by reagents such as nitric acid, Fehling s solution, thallium(III) nitrate (TTN), ytterbium(III) nitrate, ammonium chlorochromate-alumina and dayfen. In addition to the extended reaction time, most of these processes suffer from drawbacks such as the use of corrosive acids and toxic metals that generate undesirable waste products. 

Scheme 6.32 Oxidation of a-hydroxyketones with alumina-supported copper sulfate or Oxone.

Oxone has been successfully used in aprotic solvents for oxidation reactions by dispersing it on an alumina surface. Thus, the oxidation of secondary aliphatic, alicyclic and benzylic alcohols using Oxone/wet alumina oxide in CH2CI2 or CH3CN afforded ketones in good to excellent yields (70-96%). Similarly, the conversion of cycloalkanones to lactones is also reported. 

Oxidation of sulfides and sulfoxides using Oxone dispersed on silica gel or alumina was reported . A study of surface mediated reactivity of Oxone compared its reactivity with that of ferf-butyl hydroperoxide. Oxidation of sulfides to sulfones in aprotic solvents mediated by Oxone on wet montmorillonite or clay minerals proceeds in high yields. Interestingly, when Oxone on alumina is applied for selective oxidation of sulfides in aprotic solvents, the product distribution is temperature-dependent and sulfoxides or sulfones are obtained in good to excellent yields (equation 56) . ... 

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. 

Oxidation ofaUeyelie ketones to lactones.3 Cycloalkanones in CH2CI2 are oxidized to lactones by Oxone (1) mixed with slightly wet alumina as a heterogeneous mixture. Efficient stirring is necessary to obtain reproducible results. Yields are about 80% for 5- and 6-membered ketones, but are low with higher-membered ketones. 

The addition of iodine azide to double bonds gives p-iodo azides. The reagent can be prepared in situ from KI—NaNa in the presence of Oxone -wet alumina. The addition is stereospecific and anti, suggesting that the mechanism involves a cyclic iodonium ion intermediate. The reaction has been performed on many double-bond compounds, including allenes and a,p-unsaturated ketones. Similar reactions can be performed with BrNa and CfNa. 1,4-Addition has been found with acyclic conjugated dienes. In the case of BrNa, both electrophilic and free-radical mechanisms are important, whUe with CIN3 the addi-... 

There are a number of procedures for stopping at the amide stage, among them the use of concentrated H2SO4 2 equivalents of chlorotrimethylsilane followed by H20, aq. NaOH with PEG-400 and microwave irradiation, NaB03 with 4 equivalents of water and microwave irradiation, heating on neutral alumina, Oxone , and dry HCl followed by H2O. The same result can also be... 

Oxone, wet alumina, CHCI3, reflux, 15-180min, 70-96% yield. ... 

F Azizian. Removal of Arsenic from Potable Water Using Activated Alumina. Oxon, England Alcan Chemicals, 2000. 

Shin et al. have used a two-step route to obtain 2-unsubstituted pyrimidines from 2-thioxo DHPM derivatives. Oxidation of 22 using Oxone on wet alumina (method A) or hydrogen peroxide in the presence of a catalytic amount of vanadyl sulfate (method B) provided 1,4-dihydropyr-imidines 41, which were oxidized to 2-unsubstituted pyrimidines 44 by KMn04. However, 22 (X = S, O) with KMn04 furnished 2-hydroxypyri-midine 45 (Scheme 20) (09SL599). 

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