Conjugation methyl mercury

Mercury is eliminated from the body in the urine and feces, with the latter being the major route. Thus, with methyl mercury, 90% is excreted into the feces. Methyl mercury is secreted into the bile as a cysteine conjugate and undergoes extensive enterohepatic recirculation. 

Endogenous substances other than metallothionein may be involved in minimizing the effects of heavy metals and excreting them from the body. Hepatic (liver) glutathione, discussed as a phase II conjugating agent in Section 7.4, plays a role in the excretion of several metals in bile. These include the essential metals copper and zinc toxic cadmium, mercury(II), and lead(II) ions and organometallic methyl mercury. 

Another type of detoxication involves the production of cysteine conjugates, which are readily excreted. (Again, organomercury compounds show their affinity for -SH groups). Methyl mercuric cysteine is an important biliary metabolite in the rat and is degraded within the gut (presumably by microorganisms) to release inorganic mercury (see IAEA Report 137, 1972). 

Dialkyl sulphones are not reducible at a mercury cathode. Aryl alkyl and diaryl sulphones are however reduced with cleavage of a carbon-sulphur bond. Polaro-graphic half-wave potentials for this process are given in Table 5.6. One-electron addition in aprotic media to phenyl methyl sulphone [66] and to diphenyl sulphone [67] leads in both cases to a delocalised radical-anion in which the sulphone grorqj can be described as contributing a vacant symmetrical dx-orbital to the conjugated system. Phenyl methyl sulphone radical-anion is prepared and characterised in liq-... 

Vinyl substitution occurs with conjugated dienes as well as with alkenes, employing aryl-, vinyl-, methyl-, alkoxycarbonyl- or benzyl-mercury reagents and lithium tetrachloropalladate(II), but the products are usually rr-allylpalladium complexes if the reactions are carried out under mild conditions (equation 8).24,25 The ir-allylic complexes may be decomposed thermally to substituted dienes26 or reacted with nucleophiles to form allylic derivatives of the nucleophile. Secondary amines, for example, react to give tertiary allylic amines in modest yields, along with dienes and reduced dienes (equation 9).25... 

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