Tetrabutylammonium Fluoride → HCID 136016222, compound

Participants

Reaction Steps

To a solution of 2-(1-tert-butoxycarbonyl-5-phenyl-1H-thieno[3,2-c]pyrazol-3-yl)-6-(tert-butyl-dimethyl-silanyloxy)-indole-1-carboxylic acid tert-butyl ester [2.44 g, 3.78 mmol, Intermediate (48)] in tetrahydrofuran (25 mL) at 0° C. was added tetrabutylammonium fluoride (4.20 mL of a 1M THF solution, 4.20 mmol) in one portion with stirring. After 40 minutes, the reaction was partitioned between ethyl acetate (75 mL) and 10% aqueous ammonium chloride (50 mL) and the layers separated. The organics were washed with water (50 mL) and brine (50 mL) successively, dried over magnesium sulfate, and the solvent removed under reduced pressure to give an amber foam. The crude product was chromatographed on silica, eluting with 10% ethyl acetate/dichloromethane, to yield 2-(1-tert-butoxycarbonyl-5-phenyl-1H-thieno[3,2-c]pyrazol-3-yl)-6-hydroxy-indole-1-carboxylic acid tert-butyl ester [1.99 g, 99%, Intermediate (49)] as a tan foam. TLC Rf 0.31 (silica, 10% ethyl acetate/dichloromethane); LC/MS: 532.2 (M+H), RT=4.31 minutes; 1H NMR [300 Mhz, (CD3)2SO]: δ 9.73 (s, 1H), 7.84-7.81 (m, 2H), 7.76 (s, 1H), 7.61 (d, J=2 Hz, 1H), 7.56-7.44 (m, 4H), 7.07 (s, 1H), 6.84 (dd, J=2, 8 Hz, 1H), 1.71 (s, 9H), 1.40 (s, 9H).

Provenance & Evidence