2-Chloro-5-bromoaniline → (5-Bromo-2-chlorophenyl)hydrazine hydrochloride

Temperatur

5 °C

A suspension of 5-bromo-2-chloroaniline (23 g, 0.11 mol) in concentrated hydrochloric acid (150 mL) and water (90 mL) was cooled in an ice/salt bath. A solution of sodium nitrite (8 g, 0.11 mol) in water (50 mL) was added dropwise to the reaction mixture while maintaining the temperature below 4° C. After stirring for 30 minutes the suspension was transferred via cannula to a solution of SnCl2 dihydrate in concentrated hydrochloric acid (170 mL) and cooled to 5° C. The resulting thick suspension was stirred for 2 h at 5° C. and the solid was isolated via filtration. The solid was air dried and then further dried by adding chlorobutane (500 mL) and refluxing using a Dean-Stark condenser. After cooling, the solid was isolated by filtration to afford the title compound as an off-white solid (35.3 g).

1. temperaturewas cooled in an ice/salt bath
2. temperaturewhile maintaining the temperature below 4° C
3. stirringThe resulting thick suspension was stirred for 2 h at 5° C.
4. customthe solid was isolated via filtration
5. customdried
6. customfurther dried
7. additionby adding chlorobutane (500 mL)
8. temperaturerefluxing
9. temperatureAfter cooling
10. customthe solid was isolated by filtration

ORD-Eintrag

ord-caa1a57369bf467da206bf747fd6b458

Quelldatensatz

uspto-grants-2014_09

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US08822521B2