Hydrochloric Acid → 4-Hydroxy-7-methylcoumarin

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

To a mechanically stirred suspension of sodium hydride (60% in oil, 30 g, 749 mmol) in toluene (400 mL), heated at 80° C., a solution of the commercially available 2′-hydroxy-4′-methylacetophenone (50 g, 0.333 mmol) in 150 mL of toluene was added dropwise over 1 h. After complete addition, the mixture was stirred 15 min and a solution of diethyl carbonate (81 mL, 666 mmol) in toluene (500 mL) was added dropwise over 1 h. The reaction mixture was then stirred overnight at reflux. After cooling, the reaction mixture was poured into 800 mL of 2N HCl. The precipitate formed was collected by filtration, co-evaporated twice with toluene and dried under high vacuum at 55° C. 1H NMR (400 MHz, acetone-d6): 11.1 (bs, 1H), 7.76 (d, 1H), 7.18 (d, 1H), 7.14 (s, 1H), 5.60 (s, 1H), 2.47 (s, 3H).

Herkunft & Nachweise