Methyl 5-broMo-6-Methylpicolinate synthesis

Yield: 70%

Reaction Conditions:

with thionyl chloride at 20 - 65; for 2 h;Industry scale;

Steps:

10
Example 10Methyl 5-bromo-6-methyl-2-pyridine carbonate synthesisInto a 500-l. glass-lined reactor was placed 5-bromo-6-methyl-2-pyridine carboxylic acid (30 kg, 138.9 moles) and methanol (133 kg, 4156 moles). The mixture was agitated and thionyl chloride (36.8 kg, 309.2 moles) was added while the temperature was maintained between 2030° C. After the addition, the mixture was heated to 5565° C. for 2 hrs. The reaction was stopped when the raw material was detected at less than 2%. Then solvent was removed by concentration at a temperature below 40° C. MTBE (280 kg) was added and the mixture was stirred for another 30 min. to dissolve the crude. Then the MTBE solution was transferred to one drum. To the above reactor was added water (300 kg). Then the solution containing the crude was pumped to the reactor while maintaining the reactor contents at 05° C. and stirred for 1 hr. After phase separation, the aqueous layer was extracted with MTBE (60 kg). The organic phases were combined, and concentrated at a temperature below 40° C. Hexane (60 kg) was added to the residue. The obtained solid was stirred, centrifuged and dried. White powder (22.36 kg, 97.2 moles) was obtained. The purity of the product was >98%, and the mole yield was 70%.

References:

Synergetica Changzhou Chemical Company US2010/305330, 2010, A1 Location in patent:Page/Page column 3