Boron tribromide → 3-Chloro-4,5-dihydroxybenzaldehyde
Reaction equation
[Cl:1][C:2]1[C:3]([OH:12])=[C:4]([O:10]C)[CH:5]=[C:6]([CH:9]=1)[CH:7]=[O:8].B(Br)(Br)Br>ClCCl>[Cl:1][C:2]1[CH:9]=[C:6]([CH:5]=[C:4]([OH:10])[C:3]=1[OH:12])[CH:7]=[O:8]Participants
4
Reactant 2
Product 1
Reagents, catalysts & solvents 1
Conditions
- Temperature
- 0 °C
Procedure
37.2 g of commercial 5-chloro vanillin and 800 ml of dichloromethane were mixed together under nitrogen and cooled to 0° C. 300 ml of a molar solution of boron tribromide in dichloromethane are added and the mixture stood for one night at ambient temperature. It was concentrated, cooled again to 0° C. and acidified. The crystallized product was separated, washed with water, dried and crystallized from an isopropanol—water mixture (1-2 by volume) to obtain 26.6 g of the expected product melting at >260° C.
Workup
- waitthe mixture stood for one night at ambient temperature
- concentrationIt was concentrated
- temperaturecooled again to 0° C.
- customThe crystallized product was separated
- washwashed with water
- customdried
- customcrystallized from an isopropanol—water mixture (1-2 by volume)
Sources & evidence
- ORD record
- ord-1629714fd8b945d083be2677196e446f
- Source dataset
- uspto-grants-2001_11
- Patent number
- US06313305B1
Reaction notes
Loading…