4-Methyl-2-pyrone-6-acetic acid ester(s) - prepd. by heating alkyl-3-alkoxy-3-methyl-acrylate or tri:alkyl ortho-acetate with acid catalyst

摘要

New esters are of formula (I); where R is straight chain, branched or cyclic hydrocarbon residue. (I) may be hydrolysed to give the corresp. free acid. Both (I) and the free acid are useful as intermediates for pharmaceuticals, insecticides and dyestuffs. The free acid is useful also as an intermediate for higher esters of formula (I). Specific cpds. (I) include that in which R is ethyl. In an example, this is prepd. in 90% yield by treating 50 g ethyl 1-ethoxy-beta-methyl-acrylate with 1.65 g BF3.2CH3CO2H and heating the mixture (with stirring) to 150 degrees.