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Kilomentor’s Selected Oxidation Bibliography

kilomentor | 08 February, 2007 05:54

In chemical process development oxidation process steps are common either to interchange the functional groups or to assist in creating the target skeleton. Oxidation steps frequently are strongly exothermic and so on-scale may require special attention to heat transfer and cooling. But when it comes to oxidation the biggest problem for the process chemist may turn out to be choosing from the vast literature appropriate reagents and model systems to base the development upon. Over the years, Kilomentor has collected literature citations pertinent to a range of oxidative transformations that seemed particularly scalable, simple, economic, efficient, or environmentally friendly. These references are gathered below according to substrate type. Some references belong in more than one section. An abstract is given beneath the reference, which in some instances I have expanded with some more detail.


Kilomentor is trying to provide mentoring in process development for interested scientists anywhere in the world whatever their circumstance. If a reader has a particular concern or special need I can receive e-mail at kilomentor@sympatico.ca.

Kilomentor also performs consulting and group training on a fee basis.

Primary & Secondary Alcohols

Ichiro Minami and Jiro Tsuji, Tetrahedron 43(17), 3903 (1987). Dehydrogenation of Alcohols with Allyl Carbonates catalyzed by Palladium or Ruthenium Complexes.

Treatment of alkyl allyl carbonates with a phosphine-free palladium catalyst in acetonitrile affords ketones or aldehydes in high yields. Simple primary alcohols do not work. The reaction proceeds under neutral conditions hence various acid or base sensitive functional groups are not affected. Ruthenium hydride complex is also a catalyst. 1,4-Diols and 1,5-diols are converted to lactones with excess allyl methyl carbonate. Sensitive groups like vinyl alcohol, 1,2-diol, 2-hydroxy ketone and 2-hydroxy ester were simply dehydrogenated.

Douglas F. Taber, John C. Amedio, Jr. and Kang-Yeoun Jung. J. Org. Chem. 52, 5621 (1987). P2O5 / DMSO / Triethylamine (PDT): A Convenient Procedure for Oxidation of Alcohols to Ketones and Aldehydes.

The method is applicable on a large scale, is selective and uses neither cryogenic methods nor heavy metals.

Further Studies on the Utility of Sodium Hypochlorite in Organic Synthesis. Selective Oxidation of Diols and direct conversion of Aldehydes to Esters.

Sodium hypochlorite in acetic acid in acetic acid can be used for the large scale inexpensive selective oxidation of secondary alcohols to ketones in the presence of primary alcohols. The reagents oxidize a mixture of an alcohol and an aldehyde to the alcohol ester of the aldehyde, cleanly.

E. J. Corey and C.U. Kim. Tet. Lett. 12, 919 (1973). Oxidation of Primary and Secondary Alcohols to Carbonyl Compounds using Dimethyl Sulfoxide-Chlorine Complex as Reagent.

The complex reacts with primary and secondary alcohols followed by a tertiary amine to give a ketone. Double bonds are chlorinated. The reaction occurs at –45 C.

E.J. Corey and C.U. Kim. J. Am. Chem. Soc. 94(21), 7586 (1972). A New and Highly Effective Method for the Oxidation of Primary and Secondary Alcohols to Carbonyl Compounds.

Dimethyl sulfide forms a complex with N-chlorosuccinimde, which reacts to give a complex of primary and secondary alcohol that with excess tertiary amine gives the carbonyl compounds. The process fails with alcohols that can give rise to stable carbocations such as allyl or diphenylmethyl.

Jekishan R. Parikh and Willian von E. Doering. J. Am. Chem. Soc., 89(21), 5505 (1967). Sulfur Trioxide in the Oxidation of Alcohols by Dimethylsulfoxide.

Sulfur trioxide conveniently in the form of its pyridine complex and DMSO in the presence of triethylamine appears to be generally applicable to the oxidation of primary and secondary alcohols to aldehydes and ketones.

Michael P. Doyle, William J. Patrie, and Steven B. Williams, J. Org. Chem., 44(16), 2955 1979. Nickel (II) Bromide Catalyzed Oxidations of Primary and Secondary Alcohols to Carbonyl Compounds by Benzoyl Peroxide.

Primary and secondary alcohols are oxidized to their respective carbonyl compounds in high yield by benzoyl peroxide through the action of nickel(II) bromide, which serves as an effective meditative catalyst and as an alcohol template in these transformations.

Takeo Miyazawa, Takeshi Endo, Shigeo Shiihashi and Makoto Okawara, J. Org. Chem.. 50(8), 1332 (1985). Selective Oxidation of Alcohols by Oxoaminium Salts (R2N=O+X-)

The procedure is reported to be very clean but selectivity is not high.

Pier Lucio Anelli, Carlo Biffi, Farnando Montanari and Silvio Quici. J. Org. Chem. 52, 2559 (1987). Fast and Selective Oxidation of Primary Alcohols to Aldehydes or to Carboxylic Acids and of Secondary Alcohols to Ketones Mediated by Oxoammonium Salts under Phase Transfer Conditions.

Primary alcohols are quantitatively oxidized to aldehydes in a few minutes at O C in methylene chloride-0.35 M aqueous sodium hypochlorite in the presence of catalytic amounts of 4-methoxy-2,2,6,6-tetramethylpiperidine-1-oxyl. Co-catalysis by bromide and buffering at pH 8.6 with sodium bicarbonate are also required. Secondary alcohols are converted to ketones. Further oxidation of aldehydes to carboxylic acids is slow, but the reaction is completed in a few minutes under the same conditions by addition of catalytic amounts of phase-transfer catalyst. All reactions are highly selective. Only a slight excess of sodium hypochlorite is required. The method can be applied to saturated alkyl and aryl-alkyl substrates.

Joseph San Filippo Jr. and Cheun-Ing Chern. J. Org. Chem.. 42(12), 2182 (1977). Chemisorbed chromyl Chloride as a Selective Oxidant.

Chromyl chloride in methylene chloride can be adsorbed as a 10% by weigh component on Grace Davison 135 silica/alumina. Filtering the slurry leaves the reagent on the solid which in methylene chloride slurry does the oxidation under ambient conditions. Quenching with methanol and filtering removes the by-products and leaves the aldehydes and ketones.

E.J. Corey, Ernie-Paul Barrette and Plato A. Magriotis, Tet. Lett. 26(48), 5855 (1985). A New Cr(VI) Reagent for the Catalytic Oxidation of Secondary Alcohols to Ketones.

A new process is described for the oxidation of secondary alcohols to ketones using peroxyacetic acid in the presence of a catalytic amount of 2,4-dimethylpentane-2,4-diol cyclic chromate. As little as 2 mole percent of catalyst is often needed. the reaction proceeds in methylene chloride/carbon tetrachloride mixtures. the catalyst is produced in carbon tetrachloride solution. The peracid used was in ethylacetate solution. For isolation the mixture was diluted with 9:1 hexane / ether and filtered through silica gel to remove the chromium species. The reaction occurs at near zero Centigrade. The simplicity and economy of the method recommend it for large scale work. The method is likely to be sensitive to steric conditions around the alcohol group.

Secondary Alcohols not Primary Alcohols

F. M. Menger, C. Lee. J. Org. Chem. 44(19), 3446 (1979). Oxidation with Solid Potassium Permanganate.

A solid oxidant mixture, KMnO4-CuSO4 (H2O)5 converts secondary alcohols into ketones under much milder conditions and with less reagent than does permanganate on molecular sieves. The reagent does not react with double bonds and only slowly and unselectively with primary alcohols.

Robert V. Stevens, Kevin T. Chapman and Harrold L. Weller. J. Org. Chem. 45, 2032 (1980). Convenient and Inexpensive Procedure for Oxidation of Secondary Alcohols to Ketones.

Secondary alcohols are cleanly oxidized to ketones with sodium hypochloride in acetic acid in the absence of a catalyst. Methyl ketones are formed without undergoing a subsequent haloform reaction. Primary alcohols react sluggishly and preferential reaction of secondary alcohols can be obtained.

Stephen O. Nwaukwa and Philip M. Keehn. Tet. Lett. 23(1), 35 (1982). The Oxidation of Alcohols and Ethers using Calcium Hypochlorite Ca(OCl)2

Calcium hypochlorite is cheap, relatively stable, and easily stored and used solid hypochlorite oxidant, was found to oxidize secondary alcohols to ketones in excellent yields. Primary alcohols gave esters where both the acid and the alcohol portions of the ester were derived from the alcohol. Ethers were oxidized to esters but only in moderate yield.

Primary Alcohols to Aldehydes

Herbert C. Brown, G. Gundu Rao, U. Kulkarni, Synthesis, 1979 704. A Convenient Conversion of Carboxylic Acids into Aldehydes.

The procedure discloses the oxidation of boroxine esters of alcohols to aldehydes using pyridinium chlorochromate; the starting materials are readily available from borane dimethylsulfide reduction of carboxylic acids thus the merging of the reactions results in convenient conversion of acid to aldehyde without intermediate isolation.

Secondary Alcohols to Ketones: Primary Alcohols to Acids

Barry M. Trost and Yoshiro Masuyama. Tet. Lett. 25(20 173 (9184). Chemoselectivity in Molybdenum Catalyzed Alcohol and Aldehyde Oxidations.

Hydrogen peroxide in the presence of the commercially available (NH4)6Mo7O24 . 4H2O and potassium carbonate is a chemoselective method to oxidize secondary alcohols to ketones and to oxidize aldehydes to acids, the latter also accelerated by cerium chloride. Furthermore, by controlling the pH such oxidations are chemoselective in that alcohol oxidation can dominate over olefin epoxidation and a secondary alcohol over a primary one; furthermore, a hindered alcohol can be oxidized in preference to a less hindered one.

Allylic Alcohols to aldehyde or Ketone.

Ross A. Lee and Dennis S. Donald. Tet. Lett. 38(22), 2857 1997. MagtrieveTM An Efficient, Magnetically Retrievable and Recyclable Oxidant.

Presented is a mild and selective oxidant for a variety of alcohols and, in addition to being magnetically retrievable, it is superior to activated manganese dioxide in most cases particularly for less active alcohols such as simple alkyl ones. The oxidant is equally effective after treatment in recycling which is done by heat alone.

Aldehydes to Acids

Bruce Ganem, Richard P. Heggs, Alan J. Biloski and Daniel R. Schwartz. Tet. Lett. 21 685 (1980).A New Oxidation of Aldehydes to Carboxylic Acids.

2-Hydroperoxyhexafluoro-2-propanol, usefully formed from hexafluoroacetone and hydrogen peroxide, is a selective catalytic and stoichiometric reagent for the oxidation of aldehydes to acids under mildly basic conditions.

Pier Lucio Anelli, Carlo Biffi, Farnando Montanari and Silvio Quici. J. Org. Chem. 52, 2559 (1987). Fast and Selective Oxidation of Primary Alcohols to Aldehydes or to Carboxylic Acids and of Secondary Alcohols to Ketones Mediated by Oxoammonium Salts under Phase Transfer Conditions.

Primary alcohols are quantitatively oxidized to aldehydes in a few minutes at OC in methylene chloride-0.35 M aqueous sodium hypochlorite in the presence of catalytic amounts of 4-methoxy-2,2,6,6-tetramethylpiperidine-1-oxyl. Cocatalysis by bromide and buffering at pH 8.6 with sodium bicarbonate are also required. Secondary alcohols are converted to ketones. Further oxidation of aldehydes to carboxylic acids is slow, but the reaction is completed in a few minutes under the same conditions by addition of catalytic amounts of phase-transfer catalyst. All reactions are highly selective. Only a slight excess of sodium hypochlorite is required. The method can be applied to saturated alkyl and aryl-alkyl substrates.

Diols to Lactones

Michael P. Doyle, Robert L. Dow, Vahid Bagheri, and William J. Patrie, Tet. Lett. 21 2795 (1980). Selectivity in Oxidation of Diols.

Oxidation of 2,2-disubstituted –1,4-butanediols by the combination of nickel(II) bromide and benzoyl peroxide and by trityl tetrafluoroborate produce ββ-disubstituted-γ-butyrolactones with exceptional selectivity. The less sterically hindered alcohol is preferentially oxidized by these reagents.

Amines and Sulfides

Bruce Ganem, Alan J. Biloski and Richard P. Heggs, Tet. Lett. 21 689 (1980). A Biomimetic Heteroatom Oxidation.

The oxidation of amines and sulfides to N-oxides, sulfoxides, and sulfones is smoothly accomplished using 2-hydroperoxyhexafluoro-2-propanol. Sulfides are oxidized faster than amines in competitive reactions.

Baeyer-Villager Lactones and Esters

Shun-Ichi Murahashi, Yoshiaki Oda, and Takeshi Noata. Tet. Lett. 33(49) 7557 1992, Fe2O3-Catalyzed Baeyer-Villiger Oxidation of Ketones with Molecular Oxygen in the Presence of Aldehydes.

The Fe2O3-catalyzed oxidation of ketones with molecular oxygen in the presence of an aldehyde at room temperature gives the corresponding lactones or esters highly efficiently. The solvent effect is critical with benzene proving to be an excellent solvent while acetonitrile, methylene chloride and ethyl acetate are not effective. This suggests that the solvent needs to be inert to free radicals and this suggests, fluorobenzene, chlorobenzene and ααα-trifluorotoluene as possible alternatives.

Alcohol and Aldehyde to the Corresponding Ester Coupling

Further Studies on the Utility of Sodium Hypochlorite in Organic Synthesis. Selective Oxidation of Diols and Direct Conversion of Aldehydes to Esters.

Sodium hypochlorite in acetic acid in acetic acid can be used for the large scale inexpensive selective oxidation of secondary alcohols to ketones in the presence of primary alcohols. The reagents oxidize a mixture of an alcohol and an aldehyde to the alcohol ester of the aldehyde cleanly.

Levan E. Marko, Abdelaziz Mekhalfia, W. David Ollis. Synlett. 1990 347. Radical Mediated Oxidation in Organic Chemistry: 2. The Direct Preparation of Esters from Aldehydes.

A highly efficient and versatile synthesis of mixed esters from aliphatic and aromatic aldehydes and aliphatic trimethylsilyl esthers has been discovered. aromatic aldehydes require the presence of a catalytic amount of trimethylsilyl trifate to give the mixed esters directly. The reaction conditions for the esterification are neutral!

Azo compounds from Amines

S.M. Mehta and M.V. Vakilwala. J. Am. Chem. Soc. 74 563 (1952). Sodium perborate as a Reagent in Organic Chemistry. I. Preparation of Azo-Compounds.

The oxidation of substituted anilines with sodium perborate in acetic acid yields predominantly azo compounds.

Tertiary Amine Oxidation at Carbon

Shun-Ichi Murahashi, Takeshi Naotal and Koichi Yonemura. J. Am. Chem. Soc. 110, 8256 (1988). Ruthenium-Catalyzed Cytochrome P-450 Type Oxidation of Tertiary Amines with Alkyl Hydroperoxides.

Ruthenium(II)bis-triphenylphosphine dichloride has proved to be an effective catalyst for the oxidation of N,N-dimethylsubstituted anilines with t-butylhydroperoxde in dry benzene. Excess t-butylhydroperoxide can be washed away by water. Benzylic and allylic positions and carbon-carbon double bonds tolerate the oxidation. N-methyl groups are oxidized selectively in the presence of other alkyl and alkenyl groups (4:1). The intermediate leads readily to olefin/imminium cyclizations on treatment with acid.

Chien-Kuang Chen, Alfred G. Hortmann, and Mohammad R. Marzabadi. J. Am. Chem. Soc. 110, 4829 (1988). ClO2 Oxidation of Amines: Synthetic Utility and a Biomimetic Synthesis of Elaeocarpidine.

Chlorine dioxide is readily generated and stored either in aqueous or selected organic solvents at a concentration of about 0.25 M at 0-5 C. It reacts with tertiary amines to produce imminium ions which undergo hydrolysis in the presence of water. The ions can be used in the same fashion as those generated with more complications electrochemically or by mercuric acetate oxidation. Reaction in the presence of 5-7 molar equivalents of cyanide affords alpha cycano substituted tertiary amines.

Difficult Alkenes to Epoxides

Y. Kishi, M. Aratani, H. Tanino, T. Fukuyama and T. Ito, J.C.S. Chem. Comm. 1972, 64. New Epoxidation with m-Chloroperbenzoic Acid at Elevated Temperatures.

Olefins which are not electron rich and are difficult to epoxidize react at elevated temperatures with the reagent in the presence ofa radical inhibitor such as 4,4’-thiobis-(6-t-butyl-3-methylphenol) or 2,6-di-t-butyl-4-methylphenol which stabilize the oxidant to decomposition.

Alkenes to Cis 1.2-Diols

Bhushan, Rajendra Rathore, S. Chandrasekaran, Synthesis, 1984, 431-3. A Simple and Mild Method for the cis-Hydroxylation of Alkenes with Cetyltrimethylammonium Permanganate.

The reagent is reported to be stable in a brown bottle in the refrigerator for a prolonged period. The reactions can be done in methylene chloride or aqueous t-butanol with either anhydrous or aqueous work-up described.

General Oxidations

Robert E. Ireland and Longbin Liu. J. Org. Chem. 58, 2899 (1993). Improved Procedure for the Preparation of the Dess-Martin Periodinane.

The reagent is often the reagent of choice for selective oxidation of primary and secondary alcohols at room temperature and only slightly acidic pH. The reagent is too dangerous for large scale but this is a more dependable synthesis procedure.

Mark S. Cooper, Harrey Heaney, Amanda J. Newbold, William R. Sanderson, Syn Lett. 1990 533, Oxidation Reactions Using Urea-Hydrogen Peroxide; A Safe Alternative to Anhydrous Hydrogen Peroxide.

Urea-hydrogen peroxide (UHP) alone or in combination with carboxylic anhydrides has been shown to serve as an alternative to anhydrous hydrogen peroxide : the range of substrates oxidized include alkenes, ketones, sulfides (sulfones) nitrogen heterocycles (to N- oxides) and aromatic hydrocarbons (to phenols).

William P. Jackson, Synlett. 536 (1990). A Simple Preparation of Bis(trimethylsilyl) Peroxide.

Bis(trimethylsilyl) peroxide is readily prepared from hydrogen peroxide-urea complex with bistrimethylsilylurea. Ir is used in electrophilic hydroxylations, oxidation of sulfur, phosphorus and alcohols as well as Baeyer-Villiger oxidation in the presence of double bonds.

Harry Heaney, Aldrichimica Acta, 26(2) 35 (1993). Oxidation Reactions Using Magnesium Monoperphthalate and Urea Hydrogen Peroxide.

A large review with many examples using a commercial material.

Alkanes, Alkenes, Arenes and Ethers

Kimiyuki Shibuya. Syn. Comm. 24(20) 2923 (1994). A Novel Allylic Oxidation Using a Combination of Formic Acid and Selenium Dioxide.

A combination of the title reagents in dioxane is an efficient system for the allylic oxidation of olefins, in particular for sterically hindered ones, leading to the corresponding allyl alcohols or formates. The reaction is accelerated.

Mario Bressan and Antonino Morvillo. J. Chem. Soc. Chem. Commun. 1989 421. Selective Oxidation of Alkanes and Ethers mediated by Ruthenium (II) Complexes.

Selective hydroxylation (or ketonization) of cyclic alkanes and conversion of ethers to esters and of secondary alcohols to ketones, with significant rates (up to ca. 1 turnover per minute at room temperature) were achieved by using hypochlorite as oxidant and a choice of ruthenium(II) complexes as catalysts, in a biphasic water-dichloromethane system.

Per H.J. Carlsen, Tsutomu Katsuki, Victor S. Martin, K.Barry Sharpless. J. Org. Chem. 46, 3938 (1981). A Greatly Improved Procedure for Ruthenium Tetroxide Catalyzed Oxidations of Organic Compounds.

Addition of acetonitrile to the traditional carbon tetrachloride/water solvent system for ruthenium tetroxide catalyzed oxidations leads to a greatly improved sytem; some applications to olefins, alcohols, aromatic rings, and ethers are noted. Epoxides and acetates are inert. Primary alcohols are oxidized to acids. Methyl alkylethers are oxidized to methyl esters and aromatic rings are degraded to a single carbon acid. Thus methyl ethers can be masked acid functions and substituted phenyls can be masked carboxylic acids so long as other oxidizable functions are not present in the molecule.

Saul Wolfe, S.K. Hasan and John R. Cambell. Chem. Comm. 1970 1420. Ruthenium Trichloride-catalyzed Hypochlorite Oxidation of Organic Compounds.

Household bleach (sodium hypochlorite) generates ruthenium tetroxide from its lower valence states. Preparative experiments can be done in aqueous solution or suspension or, most conveniently, by stirring a methylene chloride solution of the substrate with an aqueous solution containing the catalyst and the desired amount of hypochlorite until the yellow solution turned green-black.

David M. Piatak, H.B. Bhat, and Eliahu Caspi. J. Org. Chem. 34, 112 (1969). Oxidation of Steroidal Ketones. VII. Cleavage of Steroidal Conjugated Ketones with Ruthenium Tetroxide.

When a complex structure is inexpensively available it can be cost effective to partially degrade to to get a simpler molecule still with substantial functionality and complexity. Ruthenium tetroxide has been utilized for the cleavage of conjugated and cross-conjugated steroidal ketones. In some instances the yields have been superior to those found for ozone.

D.M. Piatak, G. Herbst, J. Wicha and E. Caspi. Steroids Containing Ring A Aromatic. XIV. The Ruthenium Tetroxide Oxidation of Aromatic Steroids.

The use of ruthenium tetroxide for degrading aromatic steroids has been explored. The teroxide was generated in situ from ruthenium dioxide and sodium periodate. The solvent system is acetone/water.

Kazuhiko Sato, Masao Aoki, Masami Ogawa, Tadashi Hashimoto and Ryoji Noyori. J. Org. chem.. 61, 8310 (1996). A Practical Method for Epoxidation of Terminal Olefins with 30% Hydrogen Peroxide under Halide-Free Conditions.

Industry requires high yield, high selectivity, sufficient productivity, low cost, safety, operational simplicity and environmental consciousness. Terminal epoxides are the most difficult to oxidize. The new catalyst system consist simply of NA2WO4 dihydrate, (aminomethyl)phosphonic acid and methyltrioctylammonium bisulfate in a 2:1:1 molar ratio. The biphasic oxidation can be carried out at 90 C with 150 mole % hydrogen peroxide and 0.2-2 mol % of the catalyst without organic solvents for liquid substrates or alternatively by adding toluene to dissolve solid substrates. Styrenes do not react smoothly. The purpose of the aminomethyl phosphonic acid is unknown and is removed in later papers.

Kanzhiko Sato, Masao Aoki, Junko Takagi and Ryoji Noyori. J. Am. Chem. Soc. 119, 12386 (1997). Organic Solvent- and Halide-Free Oxidation of Alcohols with Aqueous Hydrogen Peroxide.

The aminomethylphosphonic acid has been removed from the catalyst combination. several 100 gm preparations are reported.

Gabriela Barak, Jihad Dakka and Yoel Sasson. J. Org. Chem. 53, 3553 (9188). Selective Oxidation of Alcohols by a Hydrogen Peroxide- Ruthenium trichloride system under Phase-Transfer Conditions.

The selective oxidation of primary aliphatic alcohols to carboxylic acids (60-70% selectivity) secondary alcohols to ketones (100% selectivity) and primary benzylic alcohols to aldehydes (95-100% selectivity) or carboxylic acids as well as the selective oxidation of allylic alcohols to ketones(80% selectivity) was performed at a high substrate:catalyst ratio of 625. The phase transfer catalyst protects the metal catalyst from reduction.

Shigekazu Kanemoto, Koichiro Oshima, Seijiro Matsubara and Hitosi Nozaki. Tet. Lett. 24(21) 2185 (1983). Transition-Metal Catalyzed Oxidation of Alcohols to Aldehydes and Ketones by means of Bis trimethylsilyl hydrogen peroxide.

Pyridinium dichromate-Me3SiOOSiMe3 system has been found to be effective for the oxidation of alcohols to the corresponding carbonyl compounds. The system uses catalytic chromium and avoids the gummy work-ups which often occur in chromic acid work. Primary alcohols are oxidized twenty times faster than secondary with RuCl2(PPh3)3.

Derek Pletcher and Stephen J.D. Tait. Tet. Lett. 18 1601 (1978). A Procedure for the Oxidation of Alcohols to Aldehydes based on Phase-Transfer Catalysis.

A simple and rapid lab or kilo scale method using an aqueous acid solution of potassium dichromate a methylene chloride layer and tetrabutylammonium bisulfate which can be done in a separatory funnel in minutes.

Shoji Hara and Noboru Fukasaku. J. Org. Chem. 44(5) 893 (1979). Direct Fractionation Procedure, an Improved Technique for the Quantitative Isolation of Highly Purified Chromate(VI) Oxidation Products by Urilizing Porous styrene-Divinylbenzene copolymer Gel-Liquid chromatography.

For the isolation of the products from synthetic reaction mixtures, multiple and discontinuous separation techniques such as extraction, distillation, recrystallization, or sublimation have been generally adopted. Here a reversed phase column packed with a porous styrene-divinyl benzene copolymer gel was found to exclude inorganic salts such as chromates (III and VI) by using methanol/water as eluent. Organic compounds were retained and could be separated from one another. For the case of oxidation of cholesterol to 4-cholestene-3,6-dione the yield was increased 40% to 71% and the product was colorless by this procedure with only a single peak by analytical HPLC, while using the usual method gave a pale yellow material containing trace impurities. it is thought that complete removal of chromates prevents further oxidation when the solution is being heated during isolation.

Alexander McKillop and Jonathan A. Tarbin. Tet. Lett. 24(14) 1505 (1983). Sodium Perborate- A Cheap and Effective reagent for the Oxidation of Anilines and Sulfides.

Sodium perborate in acetic acid effectively oxidizes anilines t the corresponding nitroarenes; it is also highly effective for the oxidation of sulfides to either sulfoxides or sulfones. The oxidant is used as the source of active oxygen in detergents and has no effluent problem and is very cheap.

Krzysztof Januszkiewicz and Howard Alper. Tet. Lett. 24(47) 5159 (1983). Palladium and Phase-Transfer Catalyzed Oxidation of Olefins to Ketones. Sensitivity of the Reaction to the Nature of the PhaseTransfer Agent.

Terminal Olefins can be converted to ketones in good yield, and under neutral conditions, using phase transfer catalysis; the quartenary ammonium salt governs the course of the reaction.When oxygen was bubbled at 80C through a benzene solution of 1-decene, water, palladium chloride, cupric chloride, and cetyltrimethylammonium bromide pure 2-decanone was produced in 73% yield.

Robert Louw, Hans P.W. Vermeeren, Joost A. van Asten, and Willem J. Ultee. J. C. S. Comm. 1976 496. Reaction of Sulfides with Acyl Nitrates:a simple and Rapid Method for Preparing Sulfoxides.

Sulfides react rapidly with acyl nitrates, even at –76C to give sulfoxides in high yield with no sulfone formation: either acetyl nitrate, formed from acetic anhydride and concentrated nitric acid, or, for milder conditions, benzoyl nitrate from benzoyl chloride and silver nitrate, give satisfactory results. Generally acyl nitrate made from nitric acid (98%)-Ac2O (1:2-3) at 0 C was used in situ. the sulfide was added slowly with stirring below 0 C after about 10 minutes NOx was pumped off, and the anhydride was then distilled off in vacuo. Sulfoxides containing electron attracting substituents may be too sensitive giving Pummerer rearrangement products.

General :: Comment (4) :: Permalink :: Trackbacks (0)

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George T. | 11/02/2007, 00:17

Great article!
Thanks for sharing!

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pari | 02/11/2007, 19:39

its really very useful information.
thanks for sharing.

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P B K RAO | 01/01/2008, 22:06

a nice collection of oxidation methods

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A. S. Sarma | 10/03/2008, 03:19

It is certainly a valuable & very useful review for synthetic chemists.
Incidentally, I am interested to know whether there is any suitable method for oxidation of tert-N-methyl group (eg. N-methylmorpholine)to N-carboxylic acid.

 
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