Fosfosal (CAS NO.: ), with its systematic name of , 2-(phosphonooxy)- (9CI), could be produced through many synthetic methods.

Following is one of the synthesis routes:
Firstly, 2-hydroxybenzoic acid (I) is converted by pentachloride to corresponding acyl chloride (II) upon release of phosphorous oxychloride, which reacts immediately with the free phenolic group of (II), affording the acid trichloride (III). Secondly, the compound (III) is hydrolyzed with enough water to give the 2-phosphonoxybenzoic acid (IV). Lastly, the final product is recovered from the reaction mixture by precipitation with a suitable inert organic solvent and is submitted to further purification.