Hydrochloric Acid → 2-Methyl-1-naphthol

Temperature

0 °C

To a solution of 2-formyl-1-naphtol in tetrahydrofuran (1.0 eq, 1 mmol·mL−1) was added triethylamine (1.2 eq). The solution was cooled to 0° C. and then ethyl chloroformate (1.2 eq) was added over a period of 30 min. The solution was left under stirring during 30-60 min (white precipitates formation). The precipitates (triethylamine hydrochloride) were removed by filtration and washed with tetrahydrofuran (twice less than the amount used for the reaction). To the combined filtrates were added, at 5-15° C., an aqueous solution of NaBH4 (4.0 eq, 2.6 M). When the addition was completed, the reaction mixture was stirred at room temperature for 1-2 h, then diluted with water. The solution was cooled to 0° C. and made acidic by the slow addition of aqueous HCl (10%) (FROZING!). The aqueous solution was extracted with Et2O. The organic phases were washed with dilute solution of NaOH (10%), dried (brine, MgSO4) and concentrated in vacuo to yield methylnaphtol (usually as a solid or an oil which crystallized on standing).

1. waitThe solution was left
2. customThe precipitates (triethylamine hydrochloride)
3. customwere removed by filtration
4. washwashed with tetrahydrofuran (twice less than the amount
5. customused for the reaction)
6. additionTo the combined filtrates were added, at 5-15° C.
7. additionWhen the addition
8. stirringthe reaction mixture was stirred at room temperature for 1-2 h
9. temperatureThe solution was cooled to 0° C.
10. extractionThe aqueous solution was extracted with Et2O
11. washThe organic phases were washed with dilute solution of NaOH (10%)
12. dry with materialdried (brine, MgSO4)
13. concentrationconcentrated in vacuo

ORD record

ord-fce6c4474390408abe3dbc656c5a82d7

Source dataset

uspto-grants-2016_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09409879B2