Thus, benzoxazole-4-carboxylate (I) was rearranged in ammonia at 55 C under pressure to give the target 8-hydroxy-2-methylquinazolin-4-one, although in modest yields.

In an alternative procedure, 3-methoxy-2-nitrobenzoic acid (II) was treated with SOCl2 in the presence of DMF in THF, and the resulting acid chloride (III) was converted to amide (IV) with aqueous ammonia. Catalytic hydrogenation of (IV) over Pd/C produced aniline (V), which was then acetylated with AcCl and pyridine. The crude acetylamino compound (VI) was cyclized by treatment with aqueous NaOH to yield the quinazolinone (VII). Finally, demethylation of the methoxy group of (VII) with BBr3 provided the required 8-hydroxyquinazolinone.