Toluene → HCID 59750894, compound

Participants

Reaction Steps

Under a nitrogen atmosphere, triethylamine (126 μl, 0.907 mmol) and diphenylphosphoric azide (195 μl, 0.907 mmol) were added to a toluene solution (6 ml) of the 5-[(4-chlorophenyl)sulfonyl]-5-(2,5-difluorophenyl)valeric acid (294 mg, 0.533 mmol) obtained in Example 202. The resulting mixture was stirred at room temperature for 3 hours. The reaction mixture was heated under reflux for 3 hours. After cooling to room temperature and addition of 2-methyl-2-propanol (1 ml), the mixture was stirred at 80° C. for further 18 hours. The reaction mixture was then concentrated and the residue thus obtained was dissolved in dichloromethane. The resulting solution was washed successively with a saturated aqueous solution of potassium bicarbonate, water and brine, dried over magnesium sulfate and then, concentrated. The residue thus obtained was subjected to flash chromatography on a silica gel column, and the fraction obtained from the hexane:ethyl acetate=4:1 eluate was concentrated to yield the title compound (171 mg, 0.383 mmol, 51%) as a white solid. The solid thus obtained was recrystallized from ethyl acetate-hexane, whereby colorless needle crystals were obtained.

Provenance & Evidence