62707-18-0Relevant academic research and scientific papers
The Chemistry of Aryllead(IV) Tricarboxylates. Reaction with Derivatives of Malonic Acid: New Routes to α-Aryl Carboxylic Acids and Arylated Barbituric Acid Derivatives
Kopinski, Richard P.,Pinhey, John T.,Rowe, Bruce A.
, p. 1245 - 1254 (2007/10/02)
Derivatives of 2,2-dimethyl-1,3-dioxan-4,6-dione (Meldrum's acid) and the sodium salts of substituted malonic esters undergo electrophilic C-arylation in high yield with aryllead triacetates, thus providing new routes to α-arylalkanoic acids.Syntheses of the antiflammatory compound 2-(p-isobutylphenyl)propanoic acid (Ibuprofen) have been carried out to demonstrate the method.The arylation reaction has been extended to 5-ethylbarbituric acid and to barbituric acid itself, which affords the 5,5-diarylated derivatives in good yield.A study of the effect of some tertiary bases on the reaction of p-methoxyphenyllead triacetate with the 5-isopropyl derivative of Meldrum's acid has shown that replacement of pyridine by 2,2'-bipyridyl results in an increase in yield and reaction rate, while a further marked improvement occurs in the presence of 1,10-phenanthroline.
Ester Enolates from α-Acetoxy Esters. Synthesis of Aryl Malonic and α-Aryl Alkanoic Esters from Aryl Nucleophiles and α-Keto Esters
Ghosh, Subrata,Pardo, Simon N.,Salomon, Robert G.
, p. 4692 - 4702 (2007/10/02)
Ester enolates are generated by reductive α-deacetoxylation of α-acetoxy-α-arylmalonic esters or α-acetoxy-α-arylalkanoic esters with lithium in liquid ammonia or sodium α-(dimethylamino)naphthalenide in hexamethylphosphoramide-benzene.Since the requisite α-acetoxy esters are available from aryl nucleophiles, the reductions provide effective new synthetic routes to arylmalonic esters and α-arylalkanoic esters.For example, 2-(p-isobutylphenyl)propionic acid (ibuprofen, a commercially important nonsteroidal antiinflammatory agent) is obtained in 73percent yield overall from isobutylbenzene.Arenes, aryllithiums, or arylmagnesium halides react with α-keto esters, e.g., diethyl oxomalonate, ethyl pyruvate, methyl phenylglyoxalate, or alkyl glyoxylates, to afford α-hydroxy esters.These are acetylated with acetic anhydride-triethylamine and p-(dimethylamino)pyridine as a catalyst.Reductive α-deoxygenation then allows replacement of the acetoxy group by hydrogen or an alkyl group.
THE α-ARYLATION OF DERIVATIVES OF MALONIC ACID WITH ARYLLEAD TRIACETATES. NEW SYNTHESES OF IBUPROFEN AND PHENOBARBITAL.
Pinhey, John T.,Rowe, Bruce A.
, p. 965 - 968 (2007/10/02)
Derivatives of Meldrum's acid and the sodium salts of substituted malonic acid esters undergo rapid arylation in high yield when treated with aryllead triacetates.These reactions have been applied to the synthesis of ibuprofen, an analgesic, and in a closely related reaction 5-ethylbarbituric acid has been reacted with phenyllead triacetate to give phenobarbital.
