Butane-2,3-dione monoxime

Second-order rate constants for reactions of hydroxide ion and butane-2,3-dione monoximate ion with various phosphate, phosphinate, and thiophosphinate esters pass through minima with decreasing water content of water-MeCN and water-/-BuOH mixtures. The initial inhibition is offset by stabilization of die charge-delocalized TSs.234... 

In the example included here (Expt 5.100) ethyl methyl ketone is nitrosated to butane-2,3-dione monoxime, which is then reacted with hydroxylamine to give the dioxime, dimethylglyoxime, the well-known reagent for nickel. 

The most important direct method for the determination of urea in the natural water samples is based on its reaction in acidic media with diacetyl monoxime (butane-2,3-dione monoxime), in the presence of thiosemicarbazide (hydrazinecarbothioamide), to obtain a chromogenic product that is then determined by colorimetry at 520-530 nm. The mechanism of the reaction and the structure of the chromophore have been studied at least since the study of Fearon [178], but they have not been fully understood yet. To date, the chromophore is thought to be a skipped diene carbonium cation [13,179-181]. Orthophosphate and Fe are reported to enhance the reaction [90,182,183] and thus often included in the reagents, even if this modification is not always accepted [17,180]. 

Similar to enol esters, oximes can also be used as irreversible acyl transfer agents for lipase catalysis. Thus, instead of a di-enol ester, Athavale et al. [67] polymerized diols with bis(2,3-butane dione monoxime) alkanedioate using Lipozyme IM-20. The results obtained by activation with enol-esters and their corresponding oximes were comparable. No attempts were made to analyze the end-group of the polyester. 

Butane-2,3-dione dioxime, 1590 2,3-Butanedione monoxime, 1565 t 2-Butanethiol, 1707 t Butanethiol, 1706... 

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