| 摘要 |
The invention relates to a process for the preparation of beta -ketocarboxylic acid esters of the general formula <IMAGE> (I) in which R1 is an alkyl radical having 1 to 4 C atoms, R2 is an alkyl radical or alkenyl radical having 2 to 15 C atoms or a phenyl radical and R3 is hydrogen or an alkyl or alkenyl radical having 1 to 6 C atoms, characterized in that acetocarboxylic acid esters of the general formula <IMAGE> (II) in which R1 and R3 are as defined, are reacted with calcium hydroxide or calcium oxide in the presence of an organic solvent and in the absence of water, the calcium chelate complexes formed are acylated with carboxylic acid chloride and the products are then cleaved with aqueous ammonium salt solution to form the beta -ketocarboxylic acid esters of formula (I). The beta -ketocarboxylic acid esters readily accessible by the process according to the invention can be used as important intermediates in the synthesis of pharmaceutically active ingredients or plant protection agents. |
