Hydrochloric Acid → 7-(1-Ethylpropyl)-1-methyl-1,3-dihydro-2H-benzimidazol-2-one

Participants

Reaction Conditions

Reaction Steps

A mixture of 7-(1-ethyl-1-hydroxypropyl)-1-methyl-1,3-dihydro-2H-benzimidazol-2-one (6.00 g, 25.6 mmol) and 6N HCl (20 mL) in ethanol (100 mL) was stirred at 50° C. for 3 h. The mixture was concentrated in vacuo, and the resulting residue was dissolved in ethyl acetate, washed with aqueous potassium carbonate. The organic layer was dried over magnesium sulfate, filtered, and concentrated in vacuo to give pale yellow oil, which was used in the next reaction without further purification. MS Calcd.: 216. Found: 217 (M+H). The crude material was dissolved in ethanol (150 mL). This solution was treated with 10% palladium on carbon (50% wet; 1.00 g), purged with hydrogen, and stirred under 5 atoms hydrogen for 7 h. The catalyst was removed by filtration and the filtrate was concentrated in vacuo. The residue was crystallized from ethanol/diethylether to afford the title compound as colorless crystals (3.02 g, 54%). mp 130-132° C.

Provenance & Evidence