83026-47-5

Upstream product

• 609-09-6 Diethyl ketomalonate 
• 150-78-7 1,4-dimethoxybezene 
• 83026-20-4 diethyl (2,5-dimethoxyphenyl)tartronate 
• 83026-34-0 diethyl acetoxy(2,5-dimethoxyphenyl)propanedioate 
• 74-88-4 methyl iodide 
• 609-08-5 Diethyl methylmalonate 

Downstream Products

• 83026-51-1 2-(2,5-dimethoxyphenyl)propionic acid 

Relevant academic research and scientific papers

Oxidation of Malonic Acid Derivatives by Manganese(III) Acetate. Aromatic Malonylation Reaction. Scope and Limitations

The oxidation of malonic acid derivatives RCH(COOR1)COOR2 (R1 = or R2 = H, Me, Et; R = H, Me, Et, n-Bu, i-Pr, C6H5, 4-OMeC6H4) by anhydrous or dihydrated manganese(III) acetate was studied in acetic acid in the presence of aromatic substrates at 20-80 deg C, generally with stoichiometric amounts of reagents.Electron-rich aromatics (IP 7.5 eV) underwent nuclear acetoxylation or quinone formation, the process being exclusive with anthracene and competitive with nuclear malonylation for 1- and 2-methoxynaphthalene.With other less electron-rich substrates (IP 8.5 eV) only the products coming from the oxidation of the malonic acid derivatives (aryl malonates, tartronates, etc., or dimerization and disproportionation products) were observed.The selectivity and the yield of aromatic substitution by the malonyl group was found to be affected by the electron density of the aromatic ring, the steric inhibition of substituents in the Mn(III) oxidation of the malonic acid derivative, the oxidizability of malonyl radical by Mn(III), the base (acetate ions or water) eventually present in the medium, and the further easy oxidation of the primary aryl malonate product, when unsubstituted dialkylmalonates or malonic acid were used.A mechanism is suggested in which inner-sphere electron transfer from Mn(III)-malonate complex affords Mn(II) malonyl radicals that are partitioned between oxidation, dimerization (or disproportionation), and reversible addition to the aromatics.

Ester Enolates from α-Acetoxy Esters. Synthesis of Aryl Malonic and α-Aryl Alkanoic Esters from Aryl Nucleophiles and α-Keto Esters

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.