Abstract
The oxidative desulfurization of 2-methoxy-4H-1, 3, 2-benzodioxaphosphorin 2-sulfide (salithion) by m-chloroperbenzoic acid (MCPBA) produced an isomerized product 2-methoxy-4H-1, 3, 2-benzoxathiophosphorin 2-oxide (S-benzyl salithion) as well as the expected 2-methoxy-4H-1, 3, 2-benzodioxaphosphorin 2-oxide (salioxon). The isomerization was affected by reaction solvents; it proceeded easily in chloroform but was restrained by benzene and ether. Two derivatives of salithion, 6-chloro-2-methoxy-4-methyl-1, 3, 2-benzodioxaphosphorin 2-sulfide (CMMBS) and 2-ethoxy homolog (CEMBS), were also transformed into the respective S-benzyl isomers in different degrees by MCPBA. This type of isomerization was supposed to occur through a phosphorus oxythionate intermediate generally proposed for the MCPBA oxidation of P=S compounds. When incubated with a rat liver microsomal preparation, however, salithion did not yield any S-benzyl isomer.
