PROCESS FOR PREPARATION OF ESTERS OF 2-ACETOXYALKANOIC ACIDS USING 3,6-DIALKYL-1,4-DIOXANE-2,5-DIONE OR POLY(ALPHA-HYDROXYALKANOIC ACID) AS A STARTING MATERIAL Russian patent published in 2018 - IPC C07C67/02 C07C69/67 

FIELD: biochemistry.

SUBSTANCE: invention relates to a process for preparation of a 2-acetoxyalkanoic acid ester, which comprises heating a mixture of 3,6-dialkyl-1,4-dioxane-2,5-dione, in which the alkyl groups at the 3 and 6 position may be unsubstituted or substituted by substituents which do not react under the conditions of this process with an excess of the ester of acetic acid, having a structure

to a temperature of at least 150 °C at an excess pressure in the presence of at least 0.1 moles per mole of 3,6-dialkyl-1,4-dioxane-2,5-dione alkanol or phenol, having the structure R¹-OH, and in the presence of a transesterification catalyst to convert at least a portion of the 3,6-dialkyl-1,4-dioxane-2,5-dione to the ester of 2-acetoxy-alkanoic acid, having a structure

wherein R is an alkyl group unsubstituted or substituted with an inert substituent corresponding to the alkyl groups at the 3 and 6 positions of the starting 3,6-dialkyl-1,4-dioxane-2,5-dione, and R¹ in each particular case is alkyl or aryl.

EFFECT: unlike previous methods for preparation of esters of 2-acetoxyalkanoic acid, this process proceeds with high yield and high selectivity of the desired product.

12 cl, 8 ex, 2 tbl