To a stirred mixture of 551 mg of 2,6-diphenyl-3-pyridinecarboxylic acid and 0.52 cc of diphenylphosphoryl azide in 6 cc of fluorobenzene was added dropwise 0.29 cc of triethylamine at room temperature. The resulting mixture was stirred at room temperature for 30 minutes and then heated at a temperature of 65°-70° C. for 10 minutes. After cooling, 0.45 cc of 2,6-diisopropylaniline was added and the resulting mixture was heated at a temperature of 70° C. for 1.5 hours. After cooling, water was added to the reaction mixture and extracted with chloroform. The extract was dried over magnesium sulfate, and distilled to remove the solvent. The crude product thus obtained was purified by a silica gel column chromatography (eluent: chloroform) to obtain 817 mg of compound 61.
