Hydrochloric Acid → (4-Bromo-2-fluoro-3-trifluoromethyl-phenyl)-hydrazine hydrochloride

A sample of 4-bromo-2-fluoro-3-trifluoromethyl-phenyl aniline (4 g, 15.5 mmol) is suspended in concentrated HCl (36 mL) and cooled in an ice/salt bath. The reaction is then treated dropwise with a solution of NaNO2 (1.12 g, 16.3 mmol) in water (36 mL). The reaction is allowed to stir for 30 minutes and then treated with a solution of SnCl2 dihydrate (17.5 g, 77.5 mmol) in concentrated HCl (36 mL). The reaction is then stirred for 1 hour in an ice/water bath followed by an hour at room temperature. The reaction is then filtered and the solid is treated with aqueous 50% NaOH solution (30 mL) and ether (50 mL). The aqueous phase is extracted once more with ether and the combined organics are dried over MgSO4 and filtered. The resulting solution is treated with 5 mL of 4 M HCl in dioxane while stirring and the resulting solid is collected and dried under high vacuum to afford 2.44 g of (4-Bromo-2-fluoro-3-trifluoromethyl-phenyl)-hydrazine hydrochloride; LC/MS calculated for [M+H]+ C7H5BrF4N2: 273.0, found: 272.9.

1. temperaturecooled in an ice/salt bath
2. stirringThe reaction is then stirred for 1 hour in an ice/water bath
3. waitfollowed by an hour at room temperature
4. filtrationThe reaction is then filtered
5. additionthe solid is treated with aqueous 50% NaOH solution (30 mL) and ether (50 mL)
6. extractionThe aqueous phase is extracted once more with ether
7. dry with materialthe combined organics are dried over MgSO4
8. filtrationfiltered
9. additionThe resulting solution is treated with 5 mL of 4 M HCl in dioxane
10. stirringwhile stirring
11. customthe resulting solid is collected
12. customdried under high vacuum

ORD record

ord-3b4c6fd969984dd9b5d134f7a3a52bf9

Source dataset

uspto-grants-2012_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08153671B2