Hydrochloric Acid → 2-Ethyl-5-methoxyphenol

Temperature

0 °C

Under a nitrogen atmosphere, 36.70 g (120.4 mmol) of 2-acetyl-5-methoxyphenol (1) was combined with 20.13 ml (144.4 mmol) of triethylamine in 150 mL of anhydrous THF. The reaction mixture was cooled to 0° C., and 13.81 ml (144.4 mmol) of ethyl chloroformate was added dropwise to the reaction mixture over a 30 minute period. The reaction mixture was allowed to stir for an additional 30 minutes. The resultant white solids were filtered. A solution of 13.64 g (361.1 mmol) of sodium borohydride in 200 ml of water was added dropwise to the filtrate over a period of 45 minutes at a temperature of 5-10° C. The reaction mixture was allowed to warm to room temperature and stirred for 1.5 hours. The resultant solution was acidified to pH 2 with 1M HCl and extracted with ether (1×250 ml). The ether layer was then extracted with 10% sodium hydroxide (5×100 mL). The combined base extracts were acidified with concentrated HCl and extracted with ether. The combined ether extracts were washed with water (1×100 ml), dil NaHCO3 (1×100 ml) and brine (1×100 mL), dried over sodium sulfate, filtered and concentrated in vacuo to yield 18.37 g of crude product, 2-ethyl-5-methoxyphenol (2), as a colorless oil. The crude product was used in Preparation 2 below.

1. filtrationThe resultant white solids were filtered
2. temperatureto warm to room temperature
3. stirringstirred for 1.5 hours
4. extractionextracted with ether (1×250 ml)
5. extractionThe ether layer was then extracted with 10% sodium hydroxide (5×100 mL)
6. extractionextracted with ether
7. washThe combined ether extracts were washed with water (1×100 ml), dil NaHCO3 (1×100 ml) and brine (1×100 mL)
8. dry with materialdried over sodium sulfate
9. filtrationfiltered
10. concentrationconcentrated in vacuo

ORD record

ord-9ee0fb52987a40e8ab007107c25520c4

Source dataset

uspto-grants-2004_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06803470B2