Mapping the pathway toward thiophosphinic pseudopeptides. Synthesis of suitably protected PG-Phe-Ψ[P(S)(OX)CH2]-Gly-OY analogues as thiophosphinyl dipeptide isosters (TDI), a comparative study for selective deprotection and further elongation.

In the present study, we describe in detail the first synthesis of a new class of phosphorus compounds, thiophosphinyl pseudopeptides. We prepared several fully protected thiophosphinate pseudodipeptides of the general formula PG-Phe-Ψ[P(S)(OX)CH2]-Gly-OY starting from the corresponding phosphinate pseudodipeptide using Lawesson's reagent. Selective deprotection, further elongation, and stability of these compounds were studied, and the results are disclosed. These compounds can be used as transition-state-mimicking inhibitors for several zinc metalloproteases.