Propanone dicarbonyl compounds

Reaction of lithiodithianes with acyl chlorides, esters or nitriles leads to the fOTination 1,2-dicarbonyl compounds in which one of the carbonyl groups is protected as the thioacetal. d76043j44 Optically active amino ketones of type (69) are inepared via acylation of dithiane with an oxazoline-protected (5)-serine methyl ester (Scheme 41). Optically active (5)-2-alkoxy-l-(l,3-dithian-2-yl)-l-propanones were prepaid by the reaction of the corresponding methyl (5)-lactate with 2-lithio-l,3-enantioselective synthesis of (-)-trachelanthic acid. Enantioselective synthesis of L-glyceraldehyde involves the acylation of a dithiane glycolic acid derivative followed by bikers yeast mediated reduction. ... 

It was found that the 1,3-dicarbonyl compounds were effective for use in the synthesis of l,2-dioxan-3-ols. In order to pioneer its synthetic utility, the endoperoxidation of alkenes using suifinyi-, suifonyi-, and phosphinoyl-substituted 2-propanones, which are the congener of the 1,3-dicarbonyl... 

Aqueous mixtures containing a-hydroxyketones (3-hydroxy-2-butanone, l-hydroxy-2-propanone, l-hydroxy-2-butanone) or a-dicarbonyls (2,3-butanedione, 2,3-pentanedione) and ammonium sulfide were reacted at 25 °C for 2 hr. Among the heterocyclic flavor compounds formed were oxazoles, oxazolines, thiazoles, thiazolines and pyrazines. 2-(l-Hydroxyalkyl)-3-oxazolines and 2-( 1 -hydroxyalkyl)-3-thiazolines were major intermediate compounds identified in a-hydroxyketone systems and on the other hand, 5-hydroxy-3-oxazolines and 5-hydroxy-3-thiazolines were proposed as intermediate compounds in o-dicarbonyl systems. 

To test the volatile heterocyclic conq)ounds formation under low temperature condition, 0.01 mol of one of the following carbonyl compounds including a-hydroxyketones (3-hydroxy-2-butanone, 0.88 g l-hydroxy-2-propanone, 0.74 g l-hydroxy-2-butanone 0.88g) and a-dicarbonyls (2,3-butanedione, 0.86 g 2,3-pentanedione 1.00 g) and 0.02 mol of ammonium sulfide (20% wt/wt solution in water) were dissolved in 25 mL distilled water and reacted at 25°C for 2 hours. Immediately follow the reactions, the mixtures were cooled and extracted with methylene chloride three times, dried over anhydrous sodium sulfate, and then concentrated under a stream of N2 for further GC and GC/MS analyses. 

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