Hydrazine → 4,6-Dichloro-1H-indazole
Reaction equation
[Cl:1][C:2]1[CH:9]=[C:8]([Cl:10])[CH:7]=[C:6](Cl)[C:3]=1[CH:4]=O.[NH2:12][NH2:13]>O1CCOCC1>[Cl:1][C:2]1[CH:9]=[C:8]([Cl:10])[CH:7]=[C:6]2[C:3]=1[CH:4]=[N:12][NH:13]2Participants
4
Reactant 2
Product 1
Reagents, catalysts & solvents 1
Conditions
- Temperature
- 160 °C
Procedure
In a microwave vial 2,4,6-trichlorobenzaldehyde (4.0 g, 19.1 mmol) was dissolved in 1,4-dioxane (8 mL) and hydrazine (7.2 mL, 229 mmol) was added. The vial was sealed and heated under microwave irradiation at 160° C. for 30 min. The reaction was quenched with water and extracted with EtOAc. The organic layer was washed with brine then dried over MgSO4 and concentrated. The residue was purified by silica gel chromatography with 50% to 100% EtOAc/heptane to provide 1.38 g (38%) of 4,6-dichloro-1H-indazole as a white solid. 1H NMR (CDCl3, 300 MHz): δ (ppm) 8.14 (s, 1H), 7.44 (s, 1H), 7.20 (d, J=1.5 Hz, 15H).