CAS 6018-41-3: Methyl coumalate

2-Oxo-2H-pyran-5-carboxylic acid methyl ester is an activated form of 2-oxopyran. It reacts with nucleophiles, such as malic acid, to form ethyl esters. This reaction is an example of the Friedel-Crafts reaction, which is a type of electrophilic aromatic substitution. The rate of this reaction depends on the activation energies and fluorescence properties of the reactants. The mechanism for this reaction is that the double bond in the carbonyl group is ruptured by attacking nucleophiles, resulting in a release of hydrogen gas and formation of carboxylic acid derivatives. The product can be isolated using a solvent extraction technique or purified using column chromatography.

Methyl 2-oxo-2H-pyran-5-carboxylate

Methyl coumalate is a 2-pyrone and acts as dienophile in Diels-Alder reaction. It reacts with 1,3-butadienes at 100°C to yield tetrahydrocoumarins and 4-methoxycarbonyltricyclo[3.2.1.02,7]octenes. It also reacts with cyclohexadiene to afford tetrahydronaphthalene-2-carboxylate. It undergoes Diels-Alder reaction with unactivated alkenes to afford para-substituted adducts. It has been used as reagent in phosphine-catalyzed [4+3] annulation of modified allylic carbonates. It was also used in the preparation of 7-carboxyquinolizinium derivatives. This Thermo Scientific Chemicals brand product was originally part of the Alfa Aesar product portfolio. Some documentation and label information may refer to the legacy brand. The original Alfa Aesar product / item code or SKU reference has not changed as a part of the brand transition to Thermo Scientific Chemicals.