4-Bromophenylhydrazine hydrochloride → HCID 12136728, compound

Participants

Reaction Steps

4-Bromophenylhydrazine hydrochloride (99%; 10.44 g, 1 eq) is introduced into a solution of 1,2-cyclohexadione (98%; 5.4 g, 1 eq) in absolute ethanol (50 ml). After adding 20 drops of glacial acetic acid, the mixture is stirred at room temperature for 1 h and then at 80° C. for 4 h. Then a further 5.3 g of 99% 4-bromophenylhydrazine hydrochloride are added to the reaction and, after a further 6 h at 80° C., another 5.3 g of 99% 4-bromophenylhydrazine hydrochloride are added. The reaction is stirred overnight. After 22 h, the mixture becomes viscous, so 150 ml of absolute ethanol and a further 3 g of 99% 4-bromophenylhydrazine hydrochloride are added. After a further 2 h at 80° C., the mixture is worked up. For this purpose, the solvent is distilled off. The residue is introduced gradually into polyphosphoric acid (50 g), heated to 120° C. and stirred for 1 h. The reaction output is added cautiously to ice-water and neutralized with 2M NaOH. The precipitate is filtered off and washed with distilled water. The residue is dried under reduced pressure. After recrystallization in glacial acetic acid, 5.8 g are obtained. Yield: 29.7%

Provenance & Evidence