Water → N-(4-Methoxy-7-morpholin-4-yl-benzothiazol-2-yl)-2-methyl-isonicotinamide

Participants

Reaction Steps

20.0 g Pyridine acid (115 mmol) were suspended at RT in 100 ml dichloromethane. 0.5 ml Dimethylformamide (6.5 mmol) was added, and after 0.2 h, 14.9 g oxalyl chloride (10.2 ml, 115 mmol) were added over 2 min. The dropping funnel was rinsed with 4 ml dichloromethane. The brown suspension was stirred at RT for 3 h. Then 200 ml tetrahydrofuran were added causing the acid chloride to partially precipitate. After 0.2 h, 24.3 g aminobenzothiazole (IA) (92 mmol) were added in one portion at RT. Directly afterwards, 56.0 ml N-ethyldiisopropylamine (42 g, 321 mmol) were added over 0.1 h., and the reaction mixture was stirred at RT overnight (˜17 h). The contents were heated to reflux (˜60° C.), and 300 ml water were added whilst maintaining ca. constant volume throughout a distillation process until the internal temperature reached 90° C. Once all the water was added, heating was increased to 110° C. and a total of 280 ml of distillate was collected. A further 320 ml water was added in one portion, and the temperature was increased to 120° C. whereby the internal and distillate temperature rose to ˜70° C.

Provenance & Evidence