Triethylamine → N'-(3-bromo-2-methylphenyl)isobutyrohydrazide

Temperature

-10 °C

To 3-bromo-2-methylaniline (2.5 g, 13.4 mmol) in 3N HCl (16 mL) at −10° C. NaNO2 (1.02 g, 14.78 mmol) in water (3 mL) was added dropwise. The resultant mixture was stirred for 30 minutes. SnCl2.2H2O (7.58 g, 33.6 mmol) in conc. HCl (6 mL) was added slowly to the mixture. At −10° C. the mixture was stirred for 1 h. The mixture was filtered. The solid was rinsed with cold brine, 2N HCl, and EtOAc respectively, and then dried under vacuum for 20 minutes. To the dried solid in MeOH (20 mL) was added NEt3 (1.67 mL, 11.97 mmol) and isobutyryl chloride (0.67 mL, 6.3 mmol) dropwise at 0° C. The mixture was stirred at 0° C. for 30 minutes. The mixture was concentrated and the residue was purified by flash chromatography over silica gel, using 50% EtOAc in hexane, gave N′-(3-bromo-2-methylphenyl)isobutyrohydrazide. 1H-NMR (DMSO-d6) δ 9.70 (1H, s), 7.37 (1H, s), 6.96-6.90 (2H, m), 6.62-6.59 (1H, m), 2.52-2.40 (1H, m), 2.23 (3H, s), 1.08 (6H, d, J=4.0 Hz). Mass Spectrum (ESI) m/e=270.1 (M+1).

1. customat −10° C
2. filtrationThe mixture was filtered
3. washThe solid was rinsed with cold brine, 2N HCl, and EtOAc respectively
4. customdried under vacuum for 20 minutes
5. stirringThe mixture was stirred at 0° C. for 30 minutes
6. concentrationThe mixture was concentrated
7. customthe residue was purified by flash chromatography over silica gel

ORD record

ord-5fb8b44279324b9dafa718480a217561

Source dataset

uspto-grants-2014_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08765940B2