Hydrochloric Acid → 2-Methyl-1-naphthol

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

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).

Herkunft & Nachweise