Water → 7-[(2,6-Difluorobenzyl)oxy]-2-methylpyrazolo[1,5-a]pyridine-3-carboxylic Acid ethyl Ester

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Reaction Steps

A stirred solution of 540 mg (1.00 mmol, 81% pure) of 1-amino-2-[(2,6-difluorobenzyl)oxy]pyridinium-2,4,6-trimethylbenzenesulphonate from Example 128A in DMF (10 ml) at 0° C. was admixed with 0.35 ml (3.06 mmol) of ethyl 2-butynoate and 623 mg (4.51 mmol) of potassium carbonate. The reaction mixture was stirred at room temperature overnight and added dropwise to 20 ml of water while stirring. The resulting suspension was extracted with ethyl acetate (2×20 ml). The combined organic phases were dried with a phase separation cartridge and concentrated under reduced pressure. The residue was purified by flash chromatography using a prepacked silica gel cartridge (eluent:cyclohexane-ethyl acetate 10:1 to 1:1), which gave 200 mg (25% of theory, 43% pure) of the target compound.

Provenance & Evidence