Hydrochloric Acid → 3-(4'-Chloro-3'-fluoro-4-methylbiphenyl-3-yl)-8,8-difluoro-4-hydroxy-1-azaspiro[4.5]dec-3-en-2-one

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Reaction Steps

Under nitrogen, 2.23 g (19.9 mmol) of potassium tert-butoxide were added to 8.19 g (18.0 mmol) of the compound from Example 5A in 80 ml of N,N-dimethylformamide. The reaction mixture was stirred at room temperature for 15 minutes. The reaction mixture was then added to ice-water, 1N aqueous hydrogen chloride solution was added dropwise until a pH of 1-2 had been reached, the mixture was stirred for 30 minutes and filtered off with suction, the filter cake was washed with water and the precipitate was dried. For further purification, the product was dissolved in 1N aqueous sodium hydroxide solution, precipitated by acidification with aqueous 1 N hydrochloric acid, stirred for 30 minutes, washed with water, filtered off and dried. This gave 7.50 g (97% of theory) of the title compound.

Provenance & Evidence