Sodium hydride → (e)-3-Benzo[b]thiophen-3-yl-n-methoxy-n-methyl-acrylamide

Participants

Reaction Steps

Diethyl (N-methoxy-N-methylcarbamoylmethyl)phosphonate (6.13 g, 25.6 mmol) was added dropwise via syringe to a stirred suspension of sodium hydride (1.02 g, 25.6 mmol) in anhydrous THF (75 ml) at 0° C. The reaction was warmed to room temperature and was stirred for 1 h. After cooling to 0° C., benzo[b]thiophene-3-carbaldehyde (3.78 g, 23.3 mmol) was added. The resulting mixture was stirred at room temperature for 1 hr. The reaction was quenched with 100 mL aqueous HCl (0.1 N) and extracted with ethyl acetate (250 ml). The combined organic layers were washed with brine (50 ml) and dried over anhydrous magnesium sulfate. The filtrate was concentrated in vacuo and triturated with hexane to give (E)-3-benzo[b]thiophen-3-yl-N-methoxy-N-methyl-acrylamide (5.38 g, 93%) as a yellow solid. 1H NMR (500 MHz, CDCl3) 8.06-8.01 (2H, 2 superimposed d, J=8.24, 15.87 Hz), 7.89 (1H, d, J=7.94 Hz), 7.78 (1H, s), 7.47 (1H, t, J=7.93 Hz), 7.41 (1H, t, J=8.24 Hz), 7.13 (1H, d, J=15.87 Hz), 3.79 (3H, s), 3.34 (3H, s); MS m/e 248.07 (M+H)+.

Provenance & Evidence