Ammonia → Dimiracetam

Temperature

40 °C

To a suspension of 10% palladium on charcoal (11.6 g) in water (60 ml), a solution of ethyl 3-benzyl-5-oxo-2-imidazolidinepropanoate (58 g, 0.2mol) and ammonium formate (52.9 g, 0.84 mol) in methanol (580 ml) were added. The mixture was refluxed under nitrogen for 1 hour. After cooling to 40° C., 32% ammonia (145 ml) was added and the temperature was maintained between 40 and 50° C. for 1.5 hours. After cooling to room temperature, the catalyst was removed by filtration and the solution was evaporated to dryness. The residue was diluted with water (700 ml) and stirred in the presence of ion exchange resins Amberlite IR 120 H (200 ml) and Amberlite IRA 68 (200 ml) for 1.5 hours. The resins were filtered off and washed with water (600 ml). The clear solution was evaporated under vacuum at 60° C. to afford an oil which was dried by azeotropic distillation with ethanol. The resulting residue was triturated with acetone (75 ml) to afford 19.7 g (67%) of the title compound as a white solid, m.p. 154°-157° C.

1. temperatureThe mixture was refluxed under nitrogen for 1 hour
2. temperaturethe temperature was maintained between 40 and 50° C. for 1.5 hours
3. temperatureAfter cooling to room temperature
4. customthe catalyst was removed by filtration
5. customthe solution was evaporated to dryness
6. additionThe residue was diluted with water (700 ml)
7. filtrationThe resins were filtered off
8. washwashed with water (600 ml)
9. customThe clear solution was evaporated under vacuum at 60° C.
10. customto afford an oil which
11. dry with materialwas dried by azeotropic distillation with ethanol
12. customThe resulting residue was triturated with acetone (75 ml)

ORD record

ord-1b18c181897346acb374e1e3cc18873f

Source dataset

uspto-grants-1991_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05053422