Design, Synthesis, SAR, and Molecular Modeling Studies of Acylthiocarbamates:  A Novel Series of Potent Non-nucleoside HIV-1 Reverse Transcriptase Inhibitors Structurally Related to Phenethylthiazolylthiourea Derivatives

A novel series of potent, selective HIV-1 N-acylthiocarbamate (ATC) nonnucleoside reverse transcriptase inhibitors (NNRTIs) is described. The title compounds were synthesized through a highly convergent, one-pot procedure. In cell-based assays, the lead compound (17c) prevented the HIV-1 multiplication with an EC50 of 8 μM. The lead optimization strategy was developed by single or multiple modifications of the three molecular portions, in which 17c was notionally divided. Molecular modeling studies led to the synthesis of O-(2-phthalimidoethyl)-N-(p-substituted phenyl)-N-acylthiocarbamates, which showed in vitro activities against HIV-1 in the low nanomolar range. Nevertheless, the title compounds retained low potency against HIV-1 strains carrying mutations (K103R, Y181C, and K103N/Y181C) responsible for NNRTI resistance. The hypothetical docking model of RT/17c and RT/25c, derived from X-ray crystallographic structure of a PETT derivative in complex with HIV-1 RT, revealed that the model structures of ATCs do not approximate the NNRTI butterfly-like conformation. Analysis of these hypotetical complexes helps to rationalize some SARs and resistance data.