Acetic Acid → 7-(4-Chlorophenyl)-8-isopropyl-2-methyl-chromeno[7,8-d]oxazol-6-one

Participants

Reaction Conditions

Reaction Steps

Acetic acid (20 ml) is added to polyphosphoric acid (˜25 g) heated to 80° C. The viscous solution is stirred vigorously for 5 min. 7-azido-3-(4-chlorophenyl)-2-isopropyl-chromen-4-one (1.0 g, 2.95 mmol) is added portionwise over a period of 10 min. The reaction mixture is heated at 120° C. for 3 h, cooled to room temperature and poured into water (200 ml), and the product is extracted with CH2Cl2. The organic phase is washed with water and brine, dried (MgSO4) and filtered. Methanol (30 ml) is added, followed by partial evaporation in vacuo to give a precipitate, which is isolated by filtration.

Provenance & Evidence