METHOD FOR PRODUCING 4-ALKOXY-3-HYDROXYPICOLINIC ACIDS Russian patent published in 2021 - IPC C07D213/00 C07D213/803 C07D213/84 A01N37/34 A01N43/40 C07D405/00 

FIELD: chemical engineering.

SUBSTANCE: invention relates to methods for producing a formula A compound, in particular to a method for producing a formula A compound in which R¹ means C₁-C₃ alkyl, from a formula B compound, which comprises the following stages a) for producing the first mixture, containing alkaline metal alkaline oxide of formula C, in which M means Na or K and R¹ means C₁-C₃ alkyl, solvent selected from the group comprising DMSO, methanol, sulfolane and their mixtures; and formula B compound and heating of the first mixture; b) production of the second mixture by adding water, a strong base and a metallic zinc to the first mixture; c) heating of the second mixture; and d) separation of the compound of formula A. Thus 4-alkoxy-3-hydroxypicolic acids can be easily obtained from 4,6-dibromine-3-hydroxypicolinitril with the aid of a sequence of chemical stages selected from a group comprising bromine substitution, nitrile hydrolysis and halogen reduction, which are carried out in a uniform manner. 4,6-dibrom-3-hydroxypicolintril can be obtained from furfural with a sequence of chemical stages selected from the group comprising cyanoamination, amine salt production and bromination-regrouping.

EFFECT: achieved is effective production of above-mentioned compounds.

10 cl, 11 ex