Protocatechuic Acid → Benzyl 3,4-dihydroxybenzoate

Temperature

50 °C

A solution of sodium hydroxide (6.4 g) in water (40 ml) was added to a mixture of 3,4-dihydroxybenzoic acid (24.8 g) and DMF (200 ml) which had been cooled in an ice-bath. The mixture was stirred for 20 minutes and then benzyl bromide (19.1 ml) was added dropwise. After the addition was complete, the mixture was allowed to reach ambient temperature and was stirred for 20 hours. The mixture was then warmed to 50° C. for 2 hours. The solvent was removed by evaporation and the residue was partitioned between water (300 ml) and ethyl acetate (100 ml). The ethyl acetate layer was separated and the aqueous layer extracted with ethyl acetate (100 ml). The combined ethyl acetate extracts were washed with water (100 ml), saturated sodium hydrogen carbonate solution (100 ml), water (100 ml) and with saturated sodium chloride solution (100 ml) and dried (MgSO4). The solvent was removed by evaporation to give a brown solid which was crystallised from toluene to give benzyl 3,4-dihydroxybenzoate (19 g) as a solid; m.p. 147-149° C.

1. temperaturehad been cooled in an ice-bath
2. additionAfter the addition
3. customto reach ambient temperature
4. stirringwas stirred for 20 hours
5. customThe solvent was removed by evaporation
6. customthe residue was partitioned between water (300 ml) and ethyl acetate (100 ml)
7. customThe ethyl acetate layer was separated
8. extractionthe aqueous layer extracted with ethyl acetate (100 ml)
9. washThe combined ethyl acetate extracts were washed with water (100 ml), saturated sodium hydrogen carbonate solution (100 ml), water (100 ml) and with saturated sodium chloride solution (100 ml)
10. dry with materialdried (MgSO4)
11. customThe solvent was removed by evaporation
12. customto give a brown solid which
13. customwas crystallised from toluene

ORD record

ord-df1752dc7e1c4b669aeb8d1f254d3b36

Source dataset

uspto-grants-1999_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05981531