Method for producing 2-(4-n,n-dialkylamino-2-hydroxybenzol)benzoates

摘要

The invention relates to a method for producing 2-(4-N,N-dialkylamino-2-hydroxybenzoyl)benzoates of formula (I), in which the substituents R¹ to R³, independently of one another, are defined as cited in the description. Said substances are produced as follows: L 3-N,N-dialkylamimophenol of formula (II) is reacted with phthalic anhydride of formula (III) to obtain 2-(4-N,N-dialkylamino-2-hydroxybenzoyl) benzoic acid of formula (IV) and II. said 2(4-N,N-dialkylamino-2-hydroxybenzoyl) benzoic acid of formula (IV) that has been formed in stage I. is esterified by means of a C₁-C₁₂ alcohol or a cyclic C₃-C₁₀ alcohol in the presence of an acidic catalyst to obtain 2-(4-N,N-dialkylamino-2-hydroxybenzoyl)benzoate of formula (I). The method is characterised in that the ester of formula (I) that has been formed is purified in an additional stage m by treatment with an adsorbent and/or by distillation.