Reacción #50009

Ecuación de reacción

caustic soda

tin (II) chloride

7-amino-2,4-dichloro-6-fluorobenzothiazole

sodium nitrite

→

2,4-dichloro-6-fluoro-7-hydrazinobenzothiazole

Disolventes

hydrochloric acid

hydrochloric acid

water

Condiciones de reacción

Tratamiento posterior

1. 1
   TemperaturaIt was then cooled to -5° C.
2. 2
   workup.STIRRINGThe mixture was stirred for one hour
3. 3
   Temperaturacooled to -15° C
4. 4
   Otrodid not rise above -8° C
5. 5
   workup.STIRRINGThe mixture was stirred for one hour
6. 6
   Temperaturawhilst cooling
7. 7
   Extracciónextracted with dichloromethane
8. 8
   SecadoThe extract was dried over magnesium sulfate
9. 9
   Concentraciónconcentrated

Procedimiento

14.7 g 7-amino-2,4-dichloro-6-fluorobenzothiazole was dissolved in 128 ml concentrated hydrochloric acid and the mixture stirred for 30 minutes at room temperature. It was then cooled to -5° C. and, very slowly, a solution of 4.5 g sodium nitrite in 9.5 ml water was added, dropwise. The mixture was stirred for one hour and cooled to -15° C. At this temperature, a solution of 31.5 g tin (II) chloride in 19 ml concentrated hydrochloric acid was added, dropwise at a rate that the temperature did not rise above -8° C. The mixture was stirred for one hour, made alkaline using caustic soda, whilst cooling, and extracted with dichloromethane. The extract was dried over magnesium sulfate and concentrated. Yield: 7.8 g=50% of theory m.p.: 162°-180° C.

Fuente