1,3-Dihydroxyacetone

Dihydroxyacetone (CH20HC 0) has a MW of 90. Another novel organic oxygen scavenger introduced 20 years ago with little or no commercial success, DHA is catalyzed by HQ and Mn. The reaction requires at least 2 ppm DHA per 1 ppm oxygen. 

Catalyst Glyceraldehyde Conversion Lactic Acid Yield Pyruvaldehyde Yield 1,3-Dihydroxyacetone Yield Other... 

At this time we do not have a firm nnderstanding of how CrCl2 and VCI3 catalyze the double bond isomerization and why other metal chlorides are less effective. We propose that CrCh" or VCh" anion plays a role in hydride transfer, facilitating donble bond isomerization. CnCh is less effective and both lactic acid and pyruvaldehyde are formed. FeCh" and MnCh" anions are ineffective in the transformation and only pyruvaldehyde is formed. The fact that only a small amount of 1,3-dihydroxyacetone is formed is consistent with the NMR observation that the compounds exist as hemiacetal dimers in ionic hquids and not as monomers. Otherwise 1,3-dihydroxyacetone would be expected as a major product (16). 

Hydrogenation of the carbonyl function is an important synthetic transformation and can be catalyzed by complexes of several transition metals including -among others- Co, Rh, Ru, Ir, and Os. In aqueous organometallic catalysis the first examples were given by the hydrogenation of water-soluble 2-oxo-carboxylic acids, 1,3-dihydroxyacetone and fmctose [47-54], later the same substrates were also used for testing new catalysts [29]. 

Based on our SAMP/RAMP hydrazone methodology and using our dioxanone RAMP hydrazone 96 as a chiral 1,3-dihydroxyacetone equivalent, we have been... 

Many reactions have also been carried out in water. The mechanisms of the reactions of acetone and 1,3-dihydroxyacetone using zinc-proline and related catalysts have been probed kinetically.98 The former exhibits an enamine route, whereas the latter involves rate-limiting deprotonation of the -carbon and formation of an enolate. An umbelliferyl ether of dihydroxyacetone (37) has been used as a fluorogenic probe for enolization, which may prove useful in screening of aldolases in water. 

Dihydroxyacetone gives a positive test with Benedict s reagent. 

Unlabelled 349 has been synthesized by treatment of ethyl valerimidate hydrochloride with 1,3-dihydroxyacetone in ammonia331 (equation 150). 

Bischofberger, N, Waldmann, H, Saito, T, Simon, E S, Lees, W, Bednarski, M D, Whitesides, G M, Synthesis of analogues of 1,3-dihydroxyacetone phosphate and glyceraldehyde 3-phosphate for use in studies of fructose-1,6-diphosphate aldolase, J. Org. Chem., 53, 3457-3465, 1988. 

Again in the first step of the reaction between 1,3-dihydroxyacetone monophosphate (5.41) and glyceraldehyde-3-phosphate catalysed by aldolase to form fructose-1,6-diphosphate or the reverse reaction, a ketimine (5.42) is formed between the substrate and the e-amino group of a Lys residue in the enzyme. The formation of this intermediate (5.42) can be demonstrated similarly by trapping it as a secondary amine using NaBH4 to reduce the ketimine. The glyceraldehyde-3-... 

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