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

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Reaction Steps

2.80 g (5.94 mmol) of the compound from Example 7A were initially charged in a solution of 8 ml of DMA (N,N-dimethylacetamide), a solution of 5 ml of DMA and 1.75 g (2.5 eq.) of potassium tert-butoxide was added dropwise at 20° C. and the mixture was stirred at room temperature for 4 h. The mixture was poured into 200 ml of water and the reaction was adjusted to pH 2 using concentrated aqueous hydrochloric acid, and the resulting residue was filtered off with suction. Purification by flash column chromatography (silica gel; ethyl acetate/n-hexane 1:1) gave 1.07 g (44% of theory) of the title compound.

Provenance & Evidence