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

Temperature

50 °C

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.

1. concentrationThe mixture was concentrated in vacuo
2. dissolutionthe resulting residue was dissolved in ethyl acetate
3. washwashed with aqueous potassium carbonate
4. dry with materialThe organic layer was dried over magnesium sulfate
5. filtrationfiltered
6. concentrationconcentrated in vacuo
7. customto give pale yellow oil, which
8. customwas used in the next reaction without further purification
9. custompurged with hydrogen
10. stirringstirred under 5 atoms hydrogen for 7 h
11. customThe catalyst was removed by filtration
12. concentrationthe filtrate was concentrated in vacuo
13. customThe residue was crystallized from ethanol/diethylether

ORD record

ord-0bae978b80774283b4d94f32208c7ae6

Source dataset

uspto-grants-2012_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08163935B2