Aldehydes oxidation to carboxylic acids

Toilens reagent (Section 19.3) A solution of Ag20 in aqueous ammonia used to oxidize aldehydes to carboxylic acids. 

Moreover, an electron transfer chain could be reconstituted in vitro that is able to oxidize aldehydes to carboxylic acids with concomitant reduction of protons and net production of dihydrogen (213, 243). The first enzyme in this chain is an aldehyde oxidoreductase (AOR), a homodimer (100 kDa) containing one Mo cofactor (MOD) and two [2Fe—2S] centers per subunit (199). The enzyme catalytic cycle can be regenerated by transferring electrons to flavodoxin, an FMN-con-taining protein of 16 kDa (and afterwards to a multiheme cytochrome and then to hydrogenase) ... 

Any aqueous oxidizing reagent, e.g. chromic acid (CrOs in aqueous acid), Jones reagent (CrOs in acetone) and KMn04 in basic solution, can oxidize aldehydes to carboxylic acids. 

Because you can easily further oxidize aldehydes to carboxylic acids, you can only employ mild oxidizing agents and conditions in the formation of aldehydes. Typical mild oxidizing agents include manganese dioxide (MnO), Sarett-Collins reagent (CrO,—(CSHSN)2), and pyridinium chlorochromate (PCC),... 

Dess-Martin A5-iodane 44 is an extremely useful reagent for the conversion of primary and secondary alcohols to aldehydes and ketones at 25 °C [70]. It does not oxidize aldehydes to carboxylic acids under these conditions. It selectively oxidizes alcohols in the presence of furans, sulfides, and vinyl ethers. The oxidation mechanism involves a facile ligand exchange with alcohols, followed by reductive /1-elimination. 

Aldehyde Oxidase. This enzyme is usually found in similar locations to xanthine oxidase or dehydrogenase and has been isolated from insects, birds, and mammals (20, 21). Aldehyde oxidase seems to be a poor choice of name for this enzyme because, while it oxidizes aldehydes to carboxylic acids, it also accepts a variety of purines and pyrimidines as oxidizable substrates. For example, aldehyde oxidase catalyzes the conversion of 2-hydroxypyrimidine to uracil and of adenine to 8-hydroxy-adenine (25). It appears that xanthine oxidase and aldehyde oxidase are... 

In the Shi epoxidation, an oxone (potassium persulfate, KOSO2OOH) in the presence of a fructose-derived catalyst, 7.57, generates epoxides with high enantiomeric excess oxone is best used to oxidize aldehydes to carboxylic acids in the presence of DMF. 

Benedict s reagent (Section 27.9B) A reagent for oxidizing aldehydes to carboxylic acids using a Cu salt, forming brick-red CU2O as a side product. 

Aldehydes are oxidized to carboxylic acids. Because aldehydes are generally easier to oxidize than primary alcohols, any of the reagents described in the preceding section for oxidizing primary alcohols to carboxylic acids can be used to oxidize aldehydes to carboxylic acids. 

Chromic acid oxidizes aldehydes to carboxylic acids. 

Justus von Liebig and Bernhard Tollens have discovered that milder agents such as silver oxide, Ag20 oxidize aldehydes to carboxylic acids. This reaction, which is characteristic for aldehydes, serves as a specific qualitative test for this... 

Silver ion as an oxidant is expensive but has the virtue that it selectively oxidizes aldehydes to carboxylic acids in the presence of alkenes (eq. 9.38). 

Chromic acid in acetone rapidly oxidizes aldehydes to carboxylic acids. Ketones react very slowly, or not at all. 

A Tollens test oxidizes aldehydes to carboxylic acids, bnt does not react with ketones. Which mono- and disaccharides discussed in this chapter would give a negative ToUens test ... 

Hydroperoxyhexafluoro-2-propanol has been reported to oxidize aldehydes to carboxylic acids efficiently, while alcohol groups and isolated double bonds are not attacked.The reagent is simply prepared from hydrogen peroxide and hexafluoroacetone the latter can be used in stoicheiometric or catalytic quantities. 

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