Hydrogen Bromide → 3-Hydroxyproquazone

Participants

Reaction Steps

To 0.5 g of 1-isopropyl-4-(3-methoxyphenyl)-7-methyl-2(1H)-quinazolinone is added 5 ml of 48% (aqueous) hydrobromic acid (heat evolves and the solution turns yellow). The mixture is then refluxed for 6 hours. The mixture is cooled to room temperature, then 95 ml of water added, and the resulting mixture extracted thrice with 100 ml portions of a benzene: n-butanol (8:2) mixture each extract is retained separately). Each extract is washed 4 times with 75 ml portions of water (the pH of the last wash should be neutral). The extracts are combined and evaporated to dryness to obtain a residue which is then crystallized from methanol and ethyl acetate (1:1) to obtain 1-isopropyl-4-(3-hydroxyphenyl)-7-methyl-2(1H)-quinazolinone; m.p. 270°-272°, which yields refined product upon recrystallization from methanol; m.p. 274°-275° C.

Provenance & Evidence