2-Chloro-6-methylpyridine-4-carboxylic acid → 2-Chloro-6-methyl-isonicotinic acid tert-butyl ester

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Reaction Conditions

Reaction Steps

N,N-dimethylformamide-di-tert.-butyl-acetal (19 mL, 80 mmol) is added during 40 min to a hot (65° C., flask temperature) suspension of 2-chloro-6-methyl-isonicotinic acid (3.40 g, 19.8 mmol) in dry toluene (100 mL). The clear orange solution is stirred at 80° C. for 48 h, cooled to rt and diluted with toluene (100 mL). The solution is washed with water (2×40 mL), sat. aq. NaHCO3 (3×30 mL) and sat. aq. NaCl (25 mL), dried (Na2SO4), filtered and evaporated. The residue is purified by FC (SiO2, DCM-MeOH) to give 2-chloro-6-methyl-isonicotinic acid tert-butyl ester.

Provenance & Evidence