Alkylation of Mercaptans and Inhibition of ‘SH Enzymes’ by Saligenin Cyclic Phosphate and Phosphorothiolate Esters

Abstract

Some saligenin cyclic phosphorus esters react in a mild condition with mercaptans including cysteine to yield S-salicyl thioethers. The reactivity is in the following order, which is parallel with hydrolysis rate: Phosphorothiolates>phosphates>phosphorothionates. ‘SH enzymes’ such as papain and yeast alcohol dehydrogenase were inhibited by the cyclic esters reactable with SH group. There is an interesting correlation among the alkylating activity, the inhibitory activity against ‘SH enzymes’ and the antifungal activity of the cyclic esters. A reaction mechanism is proposed and the high activity of phosphorothiolates is discussed on the basis of the data from infrared and mass spectra.