A synthetic method for unsymmetrical disulfides of cysteine: the bis-cysteine disulfide of meso-2,3-dimercaptosuccinic acid.

Abstract meso-Dimercaptosuccinic acid (DMSA) is the drug of choice for the treatment of lead-poisoning. DMSA is excreted in the urine of lead-poisoned rabbits as a conjugate with two molecules of cysteine. To confirm this, and to examine the hypothesis that DMSA may be acting as a pro-drug, we have synthesized the DMSA-bis-disulfide using novel methodology based on the use of sulfenimides derived from cysteine.