Malaprade oxidation

In the noble metal-catalyzed oxidations described above vicinal diol cleavage is sometimes observed as a side-reaction but never as a main reaction. Oxidative diol cleavage usually involves stoichiometric oxidants such as periodate (Malaprade oxidation) and there is a great need for catalytic procedures employing inexpensive, clean oxidants such as O2 or H2O2. 

By the employment of other bromides O-desmethylmycophenolic acid was obtained. Thus, the C7 bromoester methyl 6-bromo-4-methylhex-4-enoate, BrCH2CH=C(Me)CH2CH2C02Me, was prepared from tritylgeraniol which was first converted in several steps to the terminal diol, Malaprade oxidation of which furnished 4-methy-6-trityloxylhex-4-enal. Mild oxidation to, the corresponding acid with silver oxide, formation of the methyl ester with diazomethane and derivation of the required allylic bromide by treatment of the alcohol, liberated from the trityl derivative, with carbon tetrabromide containing triphenylphosphine completed the synthesis. 

L. Malaprade, Oxidation of some polyalcohols by periodic acid—applications, C. R Acad. Sci, 186 (1928) 382-384. 

MALAPRAOE LEMIEUX JOHNSON Olefin (dfoO cleavage Oxidative cleavage of 1,2-glycols to two cart nyls (Malaprade) or direct oxidation o( olefins IO4 and OSO4 catalyst (Lenveux Johnson)... 

The oxidative cleavage of v/c-diols to give two carbonyl functions (Eq. 5.3) by periodates was first observed by Malaprade and has since been widely applied to the carbohydrate area.50 Since both the reagent sodium periodate and the carbohydrate substrate are water soluble, the reaction is usually carried out in aqueous media.51 The reaction has been applied to polysaccharides such as starch.52 The periodate oxidations of sodium alginate in water as well as a dispersion in 1 1 ethanol-water mixture have been compared.53 Because sodium alginate forms a highly viscous solution, the oxidation was observed to be more extensive in ethanol-water. 

Fleury and Lange3 first pointed out that the reaction could be considered selective for hydroxyl groups attached to adjacent carbon atoms-, and they explored the application of this new reaction in the carbohydrate field. They used analytical procedures for oxidant consumption4 somewhat different from those employed by Malaprade and they applied new procedures for... 

The scope of the reaction was considerably enlarged in 1935, when Clutterbuck and Reuter6 observed that the compound tetrahydroterrein, derived from the mold metabolite terrein, consumes more than the calculated amount of periodate per mole. They found that 1,2-diketones and a-hydroxy ketones are also oxidized under the conditions used by Malaprade. Although this type of oxidation had been earlier noted [in a study7 of the action of periodate on 1,3-dihydroxy-2-propanone (dihydroxyace-tone)], Clutterbuck and Reuter made a more thorough exploration of the reaction.6 In a series of model compounds, Ri and R2 were varied from... 

Adenosine 5 -triphosphate-2, 3 -dialdehyde, MALAPRADE REACTION (PERIODATE OXIDATION)... 

The Malaprade Periodic Acid Oxidation Reaction oxidizes 1,2 diols or 2-amino alcohols with periodic acid ... 

The chemical researches were directed towards three main aims. The first dealt with periodic acid oxidation. In 1928, L. Malaprade, at the University of Nancy, hoping to specify the effect of D-mannitol upon the acidity of periodic acid, observed that the carbon-carbon linkages of the polyol were cleaved, and showed that this was a general feature of the specific reaction of periodic acid with a-glycols. Then, P. Fleury had the premonition that this acid should be an invaluable reagent for analytical purposes. He described the utilization and determination of this remarkably selective oxidant, working under mild conditions of pH and temperature. 

Oxidation with periodate under acidic conditions, the Malaprade reaction, is mainly used to introduce a large number of aldehydes into cellulose [45]. Whether a similar reaction proceeds also under conditions of natural or accelerated aging conditions has not been clarified, but corresponding processes have been postulated to occur [46]. The oxidized groups introduced are either used to further functionalize the cellulose, e.g., by reaction with... 

Oxidation of carbonyl compounds was interpreted by Malaprade as conforming to the a-glycol type by the assumption that the reaction proceeds through the hydrated form of the carbonyl group, >C(OH)2. This hypothesis is useful in interpreting the results of the oxidation of some complex compounds, intermediates of the type RCHOHCHO being oxidized like the a-glycols. 

The Editors note with regret the recent passing of Louis Malaprade, University of Nancy, discoverer of the stoichiometric oxidation of glycols by periodate, a reaction that has had such profound implications in the structural investigation of carbohydrates and of Karl Freudenberg, Heidelberg, last surviving student of Emil Fischer s, pioneer of important stereochemical concepts, and a scientist whose extensive contributions to synthesis included the classic, widely used acetone derivatives (isopropylidene acetals) of the monosaccharides. 

This method is based on the preferential oxidation of the disordered regions by sodium metaperiodate [266,267], Conditions are selected so that the reaction is confined as far as possible to the Malaprade course resulting in the formation of 2,3-dialdehyde units. The course of the reaction is followed by measuring the oxidant consumption from the amount of periodate consumed. From plots of log oxidant consumption against time, a measure of the fraction of ordered material can be calculated analogous to that of the acid hydrolysis method. 

The formation of diol-periodate esters is supported by physical evidence. The addition of ethane-1,2-diol to periodate solutions causes an initial rapid change in the uv absorption spectrum, followed by a slower change as the oxidation proceeds and lOJ is formed. Similar results are observed for other 1,2-diols except for highly substituted diols such as pinacol (Buist et al ). Buist and Bunton have shown that the cyclic periodate esters formed in alkaline solution from 1,2-diols and periodate can be detected by nmr. The initial fall in pH which occurs in the oxidations of ethane-1,2-diol and lightly substituted diols is also attributed to ester formation (Malaprade, Buist and Bunton ). Cyclic triesters, similar to the cyclic diesters formed from 1,2-diols, are formed from cyclic compounds containing the cis-l,2,3-triol system (Barker and Shaw , Dijkstra and from 1,2-0-isopropylidene-a-D-glucofuranose. In the latter case the presence of the triester has been demonstrated by nmr (Berlin and van Rudloff ). Monoesters of periodic acid have not been detected in any system, but they are postulated as intermediates in the formation of cyclic diesters from 1,2-diols (section 1.3.5). 

EtsN in CH2CI2 in the presence of 4-dimethylaminopyridine (Scheme 13.68). Dihydroxylations of the trimethylsilyl ethers of 217 and 218 generate the 4-amino-4-deoxy-heptono-1,4-lactam derivatives 219 and 220, respectively [121]. Lactam hydrolysis of 219 with LiOH, followed by the Malaprade diol cleavage with NaI04 and further oxidation and deprotection, allows the preparation of 4- p/-polyoxamic acid [122]. Lactam 217 and its enantiomer derived from (5 )-24 have been converted into all four stereomers of cw-l,2-dihydroxypyrrolizidine [123]. Compounds 217 and 218 have been used also to prepare the rm/i5 -2,3-c/5 -3,4-dihydroxyprolines [124,125]. 

Like other compounds that contain two or more - OH or - O groups on adjacent carbon atoms, carbohydrates undergo oxidative cleavage by periodic acid, HIO4 (Sec. 16.12). This reaction, introduced in 1928 by L. Malaprade (at the University of Nancy, France), is one of the most useful tools in modern research on carbohydrate structure. 

The ring size of glycosyl alkyl sulfones can be determined by periodate oxidation. It has been shown that oxidation of /3-o-glucopyranosyl phenyl sultone (26) and related analogs proceeds by stoichiometric, Malaprade-... 

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