反应详情

Oxidation of 3-(2,6-dimethyl-pyridin-4-yl)-benzoic acid methyl ester (28.8 g, 0.12 mol; prepared from commercially available 3-carboxyphenylboronic acid [CAS-No. 25487-66-5] and 4-bromo-2,6-dimethylpyridine [Chem. Pharm. Bull. 38 (1990) 2446 and J. Org. Chem. 27 (1962) 1665] as described for 3-(2-methyl-pyridin-4-yl)-benzoic acid methyl ester in example K12) with H2O2 (30%, 36.5 ml, 0.36 mol) in acetic acid (117 ml) at 70° C. for 27 h and subsequent reaction of the N-oxide in acetic acid anhydride (31 ml) at 135° C. for 30 min yielded after aqueous work-up 3-(2-acetoxymethyl-6-methyl-pyridin-4-yl)-benzoic acid methyl ester (29.2 g, 82%) as a brown oil.

1. customat 70° C.
2. customfor 27 h