1.1- Dichloroethylene epoxide

Dichloroethylene in mice is metabolised by CYP2E1 to its epoxide in a dose-dependent manner (Forkert 1999). Epoxide levels were reduced by pre-treatment with diallyl sulfone, an inhibitor of this P450 isozyme. 1,1-Dichloroethylene epoxide is formed in vivo, is localised in Clara cells, and correlates with the cytotoxicity manifested in this cell type. 

The trans isomer is more reactive than the cis isomer ia 1,2-addition reactions (5). The cis and trans isomers also undergo ben2yne, C H, cycloaddition (6). The isomers dimerize to tetrachlorobutene ia the presence of organic peroxides. Photolysis of each isomer produces a different excited state (7,8). Oxidation of 1,2-dichloroethylene ia the presence of a free-radical iaitiator or concentrated sulfuric acid produces the corresponding epoxide [60336-63-2] which then rearranges to form chloroacetyl chloride [79-04-9] (9). 

Rui L, 1 Cao, W Chen, KF Reardon, TK Wood (2004) Active site engineering of the epoxide hydrolase from Agrobacterium radiobacter ADI to enhance aerobic mineralization of cw-l,2-dichloroethylene in cells expressing an evolved toluene ort/io-monooxygenase. J Biol Chem 279 46810-46817. 

Sajus et al. [243,244] synthesized the peroxo complex of molybdenum(VI) and studied its reaction with a series of olefins. This peroxo complex M0O5 was proved to react with olefins with epoxide formation. The selectivity of the reaction increases with a decrease in the complex concentration. It was found to be as much as 95% at epoxidation of cyclohexene by M0O3 in a concentration 0.06 mol L-1 at 288 K in dichloroethylene [244], The rate of the reaction was found to be... 

The reaction proceeds as pseudomonomolecular reaction with a rate k at the constant olefin concetration. The values of k for epoxidation of olefins in dichloroethylene solutions at 288 K and an olefin concentration of 1.96 mol L 1 is given below [244]. 

Dowsley TF, Reid K, Petsikas D, Ulre-ich JB, Fisher RL, Forkert PG. 1999. Cytochrome P-450-dependent bioactivation of 1,1 -dichloroethylene to a reactive epoxide in human lung and liver microsomes. J. Pharmacol. Exp. Ther. 289 641 48... 

Pretreatment of rats with Aroclor 1254 protected against hepatotoxicity due to inhalation of 1,1-dichloro-ethylene, suggested that MFO induction by PCBs may be responsible for detoxification of 1,1-dichloro-ethylene (Reynolds et al. 1975). This detoxification might occur if the epoxide of 1,1-dichloroethylene isomerizes rapidly to an aldehyde before reacting with tissues. 

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