6065-52-7Relevant academic research and scientific papers
THE RELEVANCE OF ESTER EXCHANGE IN OXALACETIC ESTERS TO THE DECARBONMONOXYLATION REACTION
Fitzhugh, Anthony L.,Strauss, Richard S.,Brewer, Elizabeth N.,Glassman, Steven D.,Jones, Maitland
, p. 3911 - 3914 (1985)
Oxalacetic esters undergo ester exchange at 120 deg C, at which temperature loss of CO does not occur.A new mechanism is proposed for the decarbonmonoxylation reaction.
Evidence for Ketene Intermediates in the Decarbonylation of 2,4-Dioxo Acids and Esters and 2-Oxobutanedioic Acid Esters
Emerson, David W.,Titus, Richard L.,Gonzalez, Rowena M.
, p. 5301 - 5307 (2007/10/02)
The mechanism by which α,γ-dioxo carboxylic acid esters 1 and 2-oxobutanedioic acid diesters 2 lose CO was explored.The compounds, 5,5-dimethyl-2,4-dioxohexanoic acid ethyl ester, 1a, α-2-dioxocyclohexaneacetic acid ethyl ester, 1b, and α,1-dioxotetrahydro-2-naphthaleneacetic acid ethyl ester, 1c, lose CO at 170-190 deg C to yield the corresponding β-keto esters 3a-c.When compounds 1 or the parent acids 4 were heated to 170-190 deg C with water in a sealed reactor, they yielded ketones resulting from replacement by H of C(O)CO2R from 1 or C(O)CO2H from 4. β-Ketoesters suffered replacement by H of the carbethoxy group to yield the corresponding ketones when heated with water at about 105 deg C.Acylketenes, such as 4,4-dimethyl-1-pentene-1,3-dione, 6a, 2-oxo-cyclohexylidenemethanone, 6b, 1-oxotetrahydro-2-naphthylidenemethanone, 6c, 3-methyl-1-butene-1,3-dione, 6d, and 1-butene-1,3-dione, 6e, are implicated as the common intermediates that react with water to form β-keto acids that subsequently decarboxylateto yield the ketones 5.Intense IR frequencies in the region of 2120-2140 cm-1, characteristic of ketenes, are observed when 1, 2, or 3 is subjected to GC-FTIR analysis with the injector and light pipe at 280 deg C.Loss of carbon monoxide and alcohol at high temperature is required to form 6 from 1, while only the loss of alcohol at lower temperature is needed to form 6 from 3.
