2-Bromo-4-fluoroaniline → (2-Bromo-4-fluorophenyl)hydrazine

Temperature

-5 °C

Commercially available 2-bromo-4-fluoroaniline 1 (2.36 ml, 20.75 mmol) was added to a stirring solution of concentrated hydrochloric acid (40 ml) that was cooled to −5° C. This solution was allowed to age while stirring for 10 minutes. An aqueous solution of NaNO2 was added over 15 minutes. SnCl2/HCl (10.40 g, 46.1 mmol, 10 ml HCl) was added over 15 minutes and aged for an additional 30 minutes to 1 hour. The mixture was filtered and washed with dichloromethane. The resulting solid was dissolved in 1.0M HCl and extracted 3 times with dichloromethane. The organic layer was vacuum dried overnight to give 3.53 g (83% yield). 1H NMR (400 MHz, CDCl3): 7.169 (dd, J=8 Hz, J=2.8 Hz 1H), δ 7.076 (dd, J=5.2 Hz, J=9.2 Hz, 1H), 6.982 (td, J=8.4 Hz, J=2 Hz 1H), δ 5.540 (bs, 1H), δ 3.590 (bs, 1H).

1. waitaged for an additional 30 minutes to 1 hour
2. filtrationThe mixture was filtered
3. washwashed with dichloromethane
4. dissolutionThe resulting solid was dissolved in 1.0M HCl
5. extractionextracted 3 times with dichloromethane
6. customdried overnight
7. customto give 3.53 g (83% yield)

ORD record

ord-e5c91e741e0f40aab72d83a9083403ac

Source dataset

uspto-grants-2008_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07427608B2