Uses of o-hydroxybenzoylacetone in the synthesis of some substituted 2-methylchromones, chelating agents, and related materials

The nitration of o-hydroxybenzoylacetone (1) gave either the unexpected 2,3-benzofurandione a-oxime or 2-methyl-3-nitrochromone: depending on the conditions of the reaction. Nitrosation of 1 gave 1-(o-hydroxybenzoyl)propane-1,2-dione l-oxime which reacts with hydroxylamine to give 1-(o-hydroxybenzoyl)propane-1,2-dione 1,2-dioxime. Both of the oximes exhibit strong chelating properties. Bromination of 1 gave 3-bromo-2-dibromomethylchromone or 3-bromo-2-methylchromone. The condensation of diethyl malonate with 3-bromo-2-methylchromone was studied as well.