Reacción #2029586

Ecuación de reacción

sodium hydroxide

N6-propyl-4,5,6,7-tetrahydro-benzothiazole-2,6-diamine dihydrobromide

hypophosphoric acid

nitrite

→

propyl-(4,5,6,7-tetrahydro-benzothiazol-6-yl)-amine

Disolventes

hydrochloric acid

Condiciones de reacción

Tratamiento posterior

1. 1
   Otroat −30° C.
2. 2
   Otroover the course of 30 minutes
3. 3
   workup.ADDITIONis added
4. 4
   Otrois kept at −30° C
5. 5
   TemperaturaThe resulting mixture is warmed up to room temperature
6. 6
   Extracciónextracted with chloroform/ethanol 5:1 (3×250 mL)
7. 7
   SecadoThe solution is dried over anhydrous sodium sulfate
8. 8
   Concentraciónconcentrated in vacuum
9. 9
   OtroThe brown oil obtained
10. 10
    Otrois chromatographically purified over silica gel
11. 11
    Lavadoeluting with dichloromethane/methanol 97:3 under ammonia atmosphere

Procedimiento

To a solution of 14.5 g (38.9 mmol) N6-propyl-4,5,6,7-tetrahydro-benzothiazole-2,6-diamine dihydrobromide in 220 mL concentrated aqueous hydrochloric acid at −30° C. is drop wise added 66.3 mL of an aqueous 1N solution nitrite over the course of 30 minutes. After further stirring for 1 hour at the same temperature 5.44 ml (52.5 mmol) of a 50% aqueous solution hypophosphoric acid is added. The reaction mixture is stored at 4° C. overnight. After having cooled down the solution again to −30° C. the mixture is slowly basified with 40% aqueous sodium hydroxide solution while temperature is kept at −30° C. The resulting mixture is warmed up to room temperature and extracted with chloroform/ethanol 5:1 (3×250 mL). The solution is dried over anhydrous sodium sulfate and concentrated in vacuum. The brown oil obtained is chromatographically purified over silica gel, eluting with dichloromethane/methanol 97:3 under ammonia atmosphere.

Fuente