Sulfuric Acid → HCID 12585209, compound

Participants

Reaction Steps

The 3-(thiazolidin-2'-yl)-4-hydroxy-phenyl sulfonic acid hydrochloride used as the starting material for reaction with the thionyl chloride is prepared without isolating intermediates by reacting the salicylaldehyde with fuming sulfuric acid (25-45% SO3) to give 5-sulfosalicylaldehyde. Usually, the fuming sulfuric acid is employed in a quantity sufficient to provide a slight excess of SO3 over equimolar amounts of the starting aldehyde. The reaction is exothermic, usually reaching a temperature of 70° to 75° C. and may be cooled to lower temperatures of 40° to 50° C., if desired.

Provenance & Evidence