2,2-Diethoxyethylamine → 5-chloro-N-(2,2-diethoxyethyl)thiophene-2-carboxamide

Participants

Reaction Conditions

Reaction Steps

Add 5-chlorothiophene-2-carboxylic acid (100 g, 0.60 mol) and dichloromethane (1000 mL) to a 3 L three-necked round bottom flask equipped with an overhead stirrer, nitrogen inlet/outlet, addition funnel, and thermocouple. Stir the resulting solution under nitrogen while cooling to 4° C. Add via addition funnel 2,2-diethyoxyethylamine (88.5 ml, 0.60 mol) in dichloromethane (35 mL) over 12 minutes. Add 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (123 g, 0.64 mol) to the chilled mixture. Add additional dichloromethane (165 mL) and stir the reaction mixture for 22 h at room temperature. Quench the reaction with water (1000 mL) and separate the resulting layers. Back extract the aqueous layer with dichloromethane (500 mL) and combine the organic layers. Dry over sodium sulfate and purify through a silica gel bed eluting with dichloromethane followed by a mixture of 1% MeOH in dichloromethane and then a mixture of 10% MeOH in dichloromethane to afford 108 g (65%) of the title compound as a white solid. 1H NMR (500 MHz, CDCl3): δ 7.26 (d, J=3.5 Hz, 1H), 6.85 (d, J=3.5 Hz, 1H), 6.37 (bs, 1H), 4.57 (t, J=5.5 Hz, 1H), 3.68-3.74 (m, 2H), 3.48-3.57 (m, 4H), 1.19 (t, J=7.5 Hz, 6H).

Provenance & Evidence