Iodine → 5-Iodo-6-methyl-2-oxo-1-(3-(trifluoromethyl)phenyl)-1,2-dihydropyridine-3-carboxylic acid

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Reaction Steps

To acetic acid (263.7 L, 6.8 rel vol) was charged 6-methyl-2-oxo-1-[3-(trifluoromethyl)phenyl]-1,2-dihydropyridine-3-carboxylic acid (38.6 kg, 1 mol eq, limiting reagent), iodine (17.4 kg, 0.53 mol eq) and concentrated sulfuric acid (3.7 L, 0.1 rel vol). The temperature was adjusted to 50° C.-55° C. and 90% nitric acid (4.1 kg, 0.6 mol eq) charged over 15 minutes. The reaction was stirred until deemed to be complete as judged by HPLC analysis. The reaction was cooled, stirred and the product collected by filtration. The solid was washed twice with water (2×77.0 L, 2×2 rel vol) and acetone (2×38.6 kg, 2×1 rel vol). The solid was dried under vacuum to constant weight to yield the title compound (47.0 kg, 111.0 mol, 85.7%).

Provenance & Evidence