2.5- Dihydroxybenzenesulfonic acid

Chemical Name 2,5-dihydroxybenzenesulfonic acid calcium salt Common Name Hydroquinone calcium sulfonate Structural Formula oh f" ... 

Chemical Name 2,5-Dihydroxybenzenesulfonic acid calcium salt... 

The monotosylation of 2,5-dihydroxybenzenesulfonic acid is carried out in a pyridine medium by treating it with tosyl chloride, thus preferably isolating the 2-hydroxy-5-tosyloxybenzenesulfonic acid, pyridine salt. This product subjected to reflux with an alcoholic solution of piperazine yields 2-hydroxy-5-tosyloxybenzenesulfonic acid, piperazine salt. 

Chemical Name 2,5-dihydroxYbenzenesulfonic acid compound with N-ethylethanamine Common Name Diethylammonium cyclohexadien-4-ol-1-one-4-sulfonate Structural Formula ... 

Aminohydroxy-substituted xanthenes ate of Httle commercial importance. They are synthesized by condensing one mole of y -diaLkylaminophenol with phthahc anhydride, and then condensing that product with an appropriately substituted phenol. For example. Mordant Red 77 [6528-43 ] (Cl45300) (45) is prepared by condensing m- dim ethyl am in opb en o1 with phthaUc anhydride, and then condensing the product with 2,4-dihydroxybenzenesulfonic acid. 

Resorcinol (1,3-dihydroxybenzene) 159 and chlorosulfonic acid (five parts) in carbon disulfide at 0 °C or room temperature gave the 4,6-disulfonic acid 160 while with a larger excess of the reagent (ten parts) at room temperature, the 4,6-disulfonyl chloride 161 was isolated (Equation 52). When resorcinol 159 was heated with a very large excess of chlorosulfonic acid (50 parts) at 110 °C for 2 hours, the product was the 2,4,6-trisulfonyl chloride 162 and when the mixture was subjected to even more drastic reaction conditions (160-170 °C, 110 hours), the product was hexachlorobenzene. The rapid addition of chlorosulfonic acid (two equivalents) to resorcinol 159 in nitrobenzene at 15-75 °C precipitates pure 2,4-dihydroxybenzenesulfonic acid in almost quantitative yield. 

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