Hydrochloric Acid → Methyl 6-bromo-3-chloropicolinate

8.12 g (34.3 mmol) of 6-bromo-3-chloropyridine-2-carboxylic acid are admixed with 50 ml (1.25M; 62.5 mmol) of a solution of hydrogen chloride in methanol. The mixture is heated under reflux for 2 h, in the course of which 20 ml each time (1.25M; 25 mmol) of a solution of hydrogen chloride in methanol are added every 30 min. For workup, the reaction mixture is freed of the solvent on a rotary evaporator and the residue is admixed with diethyl ether and an aqueous sodium hydrogencarbonate solution. After the phase separation, the organic phase is dried; after the filtration, the filtrate is freed of the solvent on a rotary evaporator. The residue obtained is 7.78 g of the product with a purity of approx. 90% by weight.