Tetrabutylammonium Fluoride → HCID 135495104, compound

Participants

Reaction Steps

A solution of 3-[5-(tert-butyl-dimethyl-silanyloxymethyl)-1H-indol-2-yl]-1H-thieno[3,2-c]pyrazole-5-carboxylic acid methyl ester [192 mg, 0.435 mmol, Intermediate (28)] is dissolved in tetrahydrofuran (10 mL) and treated with tetrabutylammonium fluoride (1.0 M in tetrahydrofuran, 0.52 mL) and stirred overnight. The reaction mixture is diluted in ethyl acetate and washed with water, brine and dried over sodium sulfate. The residue is chromatographed on 10 g silica gel cartridge (50% ethyl acetate in heptane then ethyl acetate) to obtain solid. Recrystallization from ethyl acetate and heptane afforded 3-(5-hydroxymethyl-1H-indol-2-yl)-1H-thieno[3,2-c]pyrazole-5-carboxylic acid methyl ester [90 mg, 73%, Example 40] as beige solid; 1H NMR [(CD3)2SO)]: δ 13.66 (1H, s), 11.60 (1H, s), 7.92 (1H, s), 7.51 (1H, s), 7.38 (1H, d, J=8.2 Hz), 7.10 (1H, d, J=8.2 Hz), 6.68 (1H, s), 5.75 (1H, br s, OH), 4.54 (2H, s, —CH2OH), 3.90 (3H, s, —CO2CH3); LC/MS 328 (M++H).

Provenance & Evidence