Hydrochloric Acid → 2-Amino-4-methyl-5-(naphth-1-yl)oxazole

Participants

Reaction Conditions

Reaction Steps

A mixture of 2-acetoxy-1-(naphth-1-yl)-1-propanone (2.6 g), IMS (30 ml) and hydrochloric acid (1M; 22 ml) was boiled under reflux for 4 hours. The mixture was cooled, added to brine and extracted twice with dichloromethane. The combined organic extracts were dried with sodium sulphate, filtered and evaporated in vacuo to afford a mixture of crude 2-hydroxy-1-naphthalen-1-yl-propan-1-one and 1-hydroxy-1-naphthalen-1-yl-propan-1-one (B) as an oil (2.2 g). A portion of this material (0.5 g) was dissolved in tetrahydrofuran (2 ml) to which was added cyanamide (0.11 g), water (2 ml) and sodium hydroxide solution (2M; 0.25 ml). The mixture was stirred vigorously for 16 hours then tetrahydrofuran was added (10 ml). The mixture was heated to 40° C. for 30 minutes, cooled and left for a further 6 hours. Brine was added and the mixture was extracted twice with dichloromethane. The combined organic extracts were dried with sodium sulphate, filtered and evaporated in vacuo. The title compound (3) (0.13 g; m.p. 187-189° C.) was obtained following silica gel column chromatography of the residue in 50% ethyl acetate in petroleum ether.

Provenance & Evidence