2,2,6,6-Tetramethylpiperidine → 2,4-Difluoro-5-[hydroxy(1,3-thiazol-2-yl)methyl]-3-methylbenzoic acid

Participants

Reaction Conditions

Reaction Steps

A solution of 1.9 M n-BuLi (3.8 ml, 7.2 mmol) in hexanes was added at −30° C. to a stirred solution of 2,2,6,6-tetramethylpiperidine (1.2 g, 9.0 mmol) in THF and the mixture was stirred for an hour at the same temperature. After cooling to −78° C., a solution of 2,4-difluoro-3-methylbenzoic acid (Intermediate 46, 0.5 g, 3.0 mmol) in THF was added slowly at and the mixture was stirred for another 2 h at the same temperature. To this mixture, a solution of thiazole-2-carboxaldehyde (0.8 g, 7.2 mmol) in THF was added dropwise over a period of 10 mins and the mixture was brought to the room temperature. The reaction mixture was quenched with 1.5N hydrochloric acid and the organic layer was separated, the aqueous layer was extracted with ethyl acetate (3×10 mL) and the combined organic layer was dried over sodium sulfate. Removal of solvent afforded the title compound as colorless product. Yield: 0.42 g (51%).

Provenance & Evidence