Abstract Two metabolites of trithiozine, namely 4-(3, 5-dimethoxy-4-hydroxythiobenzoyl) morpholine S-oxide (2a) and 4-(3, 4, 5-trimethoxythiobenzoyl) morpholine S-oxide (2b), were synthesized by oxidation of the thioamides 1a, b or, in the case of 2b, by reaction of E- and Z-(3, 4, 5-trimethoxyphenyl)(methylthio) sulfine (4) with morpholine. Both procedures afford the compounds 2a, b as single isomers having the same configuration at the sulfine ...