45dihydroxybenzoic

45-dihydroxybenzoic acid, commonly written as 4,5-dihydroxybenzoic acid, is a member of the dihydroxybenzoic acid family. Its core structure is a benzene ring bearing a carboxyl group (CO2H) at position 1 and two adjacent hydroxyl groups at positions 4 and 5, giving a ortho-dihydroxy substitution pattern relative to the ring, with one hydroxy group para to the carboxyl.

Natural occurrence and synthesis of this isomer are limited compared with other dihydroxybenzoic acids. It can be prepared in laboratory settings through chemical routes that introduce hydroxyl groups onto a benzoic acid framework, or by oxidation of suitably substituted dihydroxybenzaldehyde derivatives followed by carboxylation. Protecting-group strategies and selective oxidation steps are often employed to achieve the desired 4,5-dihydroxy arrangement without over-oxidation or migration of substituents.

Chemical properties of 4,5-dihydroxybenzoic acid include the presence of two phenolic OH groups, which confer hydrogen-bonding capability and increased acidity relative to non-hydroxylated benzoic acids. The carboxyl group provides typical carboxylic-acid behavior, including ionization in aqueous solutions and the formation of water-soluble salts.

Applications and relevance are primarily in research and synthesis. The compound serves as a chemical intermediate for producing dyes, pharmaceuticals, or specialized organic materials and can function as a reference compound for studying substitution patterns on the benzoic acid ring. Safety considerations align with other phenolic acids: use appropriate protective equipment and handle with standard lab hygiene, as it can be irritant in concentrated form.