1,2-Dichloroethane → N'-((2R,3R)-2-(7-cyanobenzo[b]thiophen-4-ylamino)-3-hydroxybutanoyl)-4-fluorobenzohydrazide

Participants

Reaction Conditions

Reaction Steps

To a mixture of (2R,3R)-2-(7-cyanobenzo[b]thiophen-4-ylamino)-3-hydroxybutanoic acid (intermediate 61a) (0.56 g, 2.02 mmol), 4-fluorobenzoic hydrazide (316 mg, 2.05 mmol), HOBt (277 mg, 2.05 mmol) in THF:DMF (1:1) (30 mL) was added EDC (583 mg, 3.04 mmol) and Et3N (0.43 mL, 3.08 mmol) at 0° C. The mixture was stirred at 0° C. for 30 min., then at room temperature overnight. The reaction was quenched by adding water and extracted with EtOAc. The EtOAc extracts were washed with water, brine and dried over Na2SO4. Removal of the solvent and purification of the residue gave two fractions. The first fraction (282 mg) contained mainly the title compound and some impurities. The second fraction was the pure desired compound N′-((2R,3R)-2-(7-cyanobenzo[b]thiophen-4-ylamino)-3-hydroxybutanoyl)-4-fluorobenzohydrazide (0.42 g, 50%). 1H NMR (400 MHz, Acetone-d6, δ in ppm) 8.01 (dd, J=5.3, 8.8 Hz, 2H), 7.81 (d, J=5.7 Hz, 1H), 7.68 (d, J=5.7 Hz, 1H), 7.65 (d, J=8.2 Hz, 1H), 7.25 (t, J=8.8 Hz, 2H), 6.68 (d, J=8.2 Hz, 1H), 6.39 (d, J=7.4 Hz, 1H), 4.19˜4.26 (m, 2H), 1.39 (d, J=6.2 Hz, 3H).

Provenance & Evidence