Tetrabutylammonium Fluoride → 3-{4-[2-(4-Chloro-phenyl)-7-oxo-7H-thieno[2,3-c]pyridin-6-yl]-2-fluoro-phenoxy}-azetidine-1-carboxylic acid tert-butyl ester

Participants

Reaction Conditions

Reaction Steps

Add 2.0 M Al(CH3)3 (1.28 mL, 2.56 mmol) to a suspension of 5-(4-chloro-phenyl)-3-trimethylsilanylethynyl-thiophene-2-carboxylic acid methyl ester (0.851 g, 2.44 mmol) and 3-(4-amino-2-fluoro-phenoxy)-azetidine-1-carboxylic acid tert-butyl ester (0.688 g, 2.44 mmol) in toluene (20 mL). Stir the reaction at 60° C. for 4 h. Cool the mixture to 0° C., quench with 2.0 M NaOH (5 mL) and water (20 mL) and then extract with CHCl3 (3×50 mL). Dry with Na2SO4, filter, and concentrate. Dissolve the crude material in THF (50 mL), treat with 1.0 M TBAF (2.93 mL, 2.93 mmol) and stir at RT overnight. Dilute with EtOAc (100 mL), wash with water (3×40 mL), dry with Na2SO4, filter, and concentrate. Purify the crude material by chromatography, eluting with 5% CH3OH/CHCl3 to give 1.03 g (80%) of the title compound. LC-MS/ES m/z (35Cl) 526.9 [M+H]+.

Provenance & Evidence