Reaction equation
C[O:2][C:3]1[CH:11]=[C:10]([O:12][CH3:13])[C:9]([O:14][CH3:15])=[CH:8][C:4]=1[C:5]([OH:7])=[O:6].[Na+].[Br-].B(F)(F)F.CCOCC.[OH-].[Na+]>C(OCC)(=O)C.O>[OH:2][C:3]1[CH:11]=[C:10]([O:12][CH3:13])[C:9]([O:14][CH3:15])=[CH:8][C:4]=1[C:5]([OH:7])=[O:6]Participants
Conditions
- Temperature
- 40 °C
Procedure
In 10 g of ethyl acetate were suspended 2.0 g of 2,4,5-trimethoxybenzoic acid (1a) and 1.45 g of NaBr in a stream of argon, to which 4.0 g of BF3.Et2O was then added dropwise at 25° C., followed by heat stirring at 40° C. for 3 hours. The reaction mixture was cooled with ice, to which 10 mL of water was then added dropwise at 10° C., followed by dropwise adding 7.5 g of a 25% (w/w) sodium hydroxide aqueous solution. Thereto was further added 10 mL of water before stirring, followed by filtering off insoluble inorganic matter. To the separated aqueous layer was dropwise added 3.94 g of 35% hydrochloric acid, followed by stirring for 10 minutes. The precipitated crystal was collected by filtration and washed with water. The resultant crystal was then dried under reduced pressure at 60° C. to provide 1.7 g of 2-hydroxy-4,5-dimethoxybenzoic acid (2a) at a yield of 91%.
Workup
- temperatureby heat
- additionwas then added dropwise at 10° C.
- stirringbefore stirring
- filtrationby filtering off insoluble inorganic matter
- stirringby stirring for 10 minutes
- filtrationThe precipitated crystal was collected by filtration
- washwashed with water
- customThe resultant crystal was then dried under reduced pressure at 60° C.
Sources & evidence
- ORD record
- ord-a5126c13cb174211811fcc74d1968deb
- Source dataset
- uspto-grants-2014_09
- Patent number
- US08841461B2
Linked notes
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