p-Toluenesulfonic acid monohydrate → 3-(5-Bromo-2-methylphenyl)-4-hydroxy-1-azaspiro[4.5]dec-3-ene-2,8-dione

Participants

Reaction Conditions

Reaction Steps

192 mg (1.01 mmol) of 4-toluenesulphonic acid monohydrate were added to 2.49 g (6.32 mmol) of 11-(5-bromo-2-methylphenyl)-12-hydroxy-1,4-dioxa-9-azadispiro[4.2.4.2]tetradec-11-en-10-one (Example 38A) in 26 ml of acetone and 13 ml of water. The reaction mixture was stirred at 80° C. overnight. For work-up, the cold reaction mixture was diluted with water and acetone was removed on a rotary evaporator. The precipitated crude product was extracted with ethyl acetate. The organic phase was washed with saturated aqueous sodium chloride solution, dried over sodium sulphate and concentrated under reduced pressure. Drying gave 1.97 g (89% of theory) of the title compound.

Provenance & Evidence