Reaction #62824

Reaction equation

6,7-Dichloro-3-methyl-4-hydroxy-4-thioureidocarbonyl-2-oxo-1,2,3,4-tetrahydroquinazoline

dimethylformamide

sodium hydride

ethyl bromide

→

6,7-dichloro-3-methyl-spiro[1,2,3,4-tetrahydroquinazoline-4,4'-imidazolidine]-2,2',5'-trione

Conditions

Workup

1. 1
   workup.STIRRINGthe mixture is further stirred for 30 minutes
2. 2
   workup.DISTILLATIONthe solvent is distilled off under reduced pressure
3. 3
   workup.ADDITIONTo the residue [i.e. 6,7-dichloro-3-methyl-4-hydroxy-4-(2-methylisothioureido)-carbonyl-2-oxo-1,2,3,4-tetrahydroquinazoline] is added 10% hydrochloric acid (30 ml)
4. 4
   workup.STIRRINGthe mixture is stirred at 70° C. for 4 hours
5. 5
   TemperatureAfter cooling
6. 6
   Filtrationthe precipitates are taken by filtration
7. 7
   Washwashed with 10% aqueous sodium hydrogen carbonate solution
8. 8
   Otherrecrystallized from dimethylformamide-water

Procedure

6,7-Dichloro-3-methyl-4-hydroxy-4-thioureidocarbonyl-2-oxo-1,2,3,4-tetrahydroquinazoline (2.8 g) is dissolved in dimethylformamide (30 ml), and thereto is added sodium hydride (60% oily suspension) (0.32 g), and the mixture is stirred at room temperature for 30 minutes. To the mixture is added ethyl bromide (2 ml), and the mixture is further stirred for 30 minutes, and then the solvent is distilled off under reduced pressure. To the residue [i.e. 6,7-dichloro-3-methyl-4-hydroxy-4-(2-methylisothioureido)-carbonyl-2-oxo-1,2,3,4-tetrahydroquinazoline] is added 10% hydrochloric acid (30 ml), and the mixture is stirred at 70° C. for 4 hours. After cooling, the precipitates are taken by filtration, washed with 10% aqueous sodium hydrogen carbonate solution and then recrystallized from dimethylformamide-water to give 6,7-dichloro-3-methyl-spiro[1,2,3,4-tetrahydroquinazoline-4,4'-imidazolidine]-2,2',5'-trione (1.4 g).

Source