Tetrabutylammonium Fluoride → 2-(1-tert-butoxycarbonyl-1H-thieno[3,2-c]pyrazol-3-yl)-5-hydroxy-indole-1-carboxylic acid tert-butyl ester

Participants

Reaction Conditions

Reaction Steps

To a solution of 2-(1-tert-butoxycarbonyl-1H-thieno[3,2-c]pyrazol-3-yl)-5-(tert-butyl-dimethyl-silanoxy)-indole-1-carboxylic acid tert-butyl ester (320 mg, 0.56 mmol, Example 5C) in tetrahydrofuran (5 mL) at 0° C. is added TBAF (1.0 M in tetrahydrofuran, 0.67 mL, 0.67 mmol). The solution is stirred at 0° C. for 30 minutes. The solvent is then removed and the residue is chromatographed through silica gel (dichloromethane-ethyl acetate, 95:05 to 90:10 as eluant) to produce 205 mg (80%) 2-(1-tert-butoxycarbonyl-1H-thieno[3,2-c]pyrazol-3-yl)-5-hydroxy-indole-1-carboxylic acid tert-butyl ester as an orange foam. LC/MS: RT=3.74 minutes, 456.0 m/e.

Provenance & Evidence