Imidazole → N'-((2R,3S)-3-(tert-butyldimethylsilyloxy)-2-(7-cyanobenzo[b]thiophen-4-ylamino)butanoyl)-4-cyanobenzohydrazide

Participants

Reaction Steps

To a solution of 4-cyano-N′-((2R,3S)-2-(7-cyanobenzo[b]thiophen-4-ylamino)-3-hydroxybutanoyl)benzohydrazide (320 mg, 0.76 mmol) in DMF (10 mL) was added imidazole (208 mg, 3.06 mmol) and TBSCl (230 mg, 1.53 mmol) at 0° C. After addition, the mixture was allowed to warm to room temperature and stirred overnight. The reaction was quenched by adding ice-water and extracted with EtOAc. The EtOAc extracts were washed with water, brine and dried over Na2SO4. Removal of the solvent gave a residue, which was purified by SiO2 column to afford N′-((2R,3S)-3-(tert-butyldimethylsilyloxy)-2-(7-cyanobenzo[b]thiophen-4-ylamino)butanoyl)-4-cyanobenzohydrazide (380 mg, 93%). 1H NMR (400 MHz, CDCl3, δ in ppm) 9.28 (b, 1H), 8.63 (b, 1H), 7.77 (d, J=8.4 Hz, 2H), 7.63 (d, J=8.4 Hz, 2H), 7.45 (d, J=8.2 Hz, 1H), 7.42 (d, J=5.6 Hz, 1H), 7.23 (d, J=5.6 Hz, 1H), 6.35 (d, J=8.2 Hz, 1H), 5.59 (d, J=5.9 Hz, 1H), 4.44 (m, 1H), 4.01 (m, 1H), 1.14 (d, J=6.3 Hz, 3H), 0.83 (s, 9H), 0.03 (s, 3H), 0.00 (s, 3H).

Provenance & Evidence