log Pvalues and the polar surface area (PSA) values were calculated. Substitution of the methylsulfinyl group (CH3S(O)–R) in 6-MITC with a formyl (CHO–R), a methylsulfanyl (CH2S–R) or a methyl (CH3–R) group reduced the activities of the parent isothiocyanate. Substitution with a formylgroup resulted in lower lipophilicity (log Pvalue) whereas substitution with a methylsulfanyl or methyl group resulted