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

Participants

Reaction Conditions

Reaction Steps

A solution of 2-(1-tert-butoxycarbonyl-1H-thieno[3,2-c]pyrazol-3-yl)-5-(tert-butyl-dimethyl-silanyloxymethyl)-indole-1-carboxylic acid tert-butyl ester [3.8 g, 6.51 mmol, Intermediate (9)]) in anhydrous tetrahydrofuran (40 mL) is cooled to 0° C. To it is added tetrabutylammonium fluoride (1M in tetrahydrofuran, 10 mL) drop wise. Stirred at 0° C. for 20 minutes then at room temperature for 20 minutes. Water (20 mL) is added and extracted three times with ethyl acetate (30 mL). The combined ethyl acetate phases are washed with brine and dried over sodium sulfate. The residue is chromatographed on 35 g silica gel (10-50% ethyl acetate in heptane) to give 2-(1-tert-butoxycarbonyl-1H-thieno[3,2-c]pyrazol-3-yl)-5-hydroxymethyl-indole-1-carboxylic acid tert-butyl ester [2.63 g, 85%, Intermediate (10)] as white solid; 1H NMR [(CD3)2SO)]: δ 8.05 (2H, m), 7.62 (1H, s), 7.38 (2H, m), 7.02 (1H, s), 5.21 (1H, t), 4.6 (2H, d), 1.64 (9H, s), 1.25 (9H, s); LC/MS: 470 (M+H).

Provenance & Evidence