Dimethylformamide → Nik 228

Participants

Reaction Conditions

Reaction Steps

In 100 ml of n-butanol were heated 30.0 g of 2-aminobenzothiazole and 25.0 g of propargyl bromide at 100° C. for 6 hours. After cooling, the precipitated crystals were taken out by filtration and recrystallized from water to give 40.0 g of the intermediate. Next, the intermediate was added to 250 ml of sodium ethoxideethanol solution (Na, 3.3 g). The mixture was heated under reflux for one hour. After completion of the reaction, the solvent was removed and water was added to the residue. The precipitated crystals were taken out by filtration to give 22.4 g of 2-methylimidazo[2,1-b]benzothiazole. The benzothiazole was added to a mixture of 300 ml of dry dimethylformamide and 30.0 ml of phosphorus oxychloride followed by heating at 60° C. for 6 hours. After completion of the reaction, the reaction mixture was poured onto 1 liter of chilled water and then was neutralized with ammonium hydroxide. Then, the precipitated crystals were taken out by filtration. The thus obtained formyl compound, 20.5 g, was suspended in 300 ml of methanol and 1.5 g of sodium borohydride was added to the suspension followed by stirring at room temperature for 2 hours. After methanol was removed, the residue was treated with 200 ml of water and filtered to give 20.0 g of the title compound.

Provenance & Evidence