Toluene → N-(2-(4-chlorophenyl)ethyl)-3-hydroxypyridine-2-Carboxamide

Participants

Reaction Conditions

Reaction Steps

A stirred mixture of 3-hydroxypyridine-2-carboxylic acid (1.39 g, 0.01 mol) in dry THF (60 mL) under argon was cooled to −20° C. To this was added all at once a 20% solution of phosgene in toluene (5.1 g, 0.01 mol) and the resulting mixture was stirred for 90 minutes while the temperature slowly rose to 0° C. The reaction mixture was then recooled to −20° C. and a solution of diisopropylethylamine (2.58 g, 0.02 mol) in THF (20 mL) was added dropwise over 30 minutes. After the addition was complete, the mixture was stirred an additional 2 hours as the temperature was slowly brought to 0° C. Stirring was continued at 0° C. overnight. To this stirred mixture was added, all at once, 2-(4-chlorophenyl)ethylamine (1.56 g, 0.01 mol), and the resulting mixture was stirred at room temperature for 6 hours. The mixture was diluted with ether (100 mL), washed with 1N HCl (100 mL), dried (MgSO4) and concentrated to give the title compound as an off-white solid (1.95 g). The mass spectrum showed the expected 3:1 parent ion ratio at m/e 276 and 278. Coupling Procedure B: Preparation of 3-Hydroxy-4-methoxy-N-(4-(4-trifluoromethylphenoxy)phenyl)-pyridine-2-carboxamide (425).

Provenance & Evidence