Synthesis and Antiviral Bioactivity of Chiral Thioureas Containing Leucine and Phosphonate Moieties

A series of novel chiral thioureas 3a-n bearing leucine and phosphonate moieties were synthesized in excellent yields. The structures of the compounds were completely characterized by elemental analysis, IR,( 1)H-, (13)C-, (31)P- and (19)F-NMR spectral data. A half-leaf method was used to determine the in vivo protective and curative efficacies of the title products against tobacco mosaic virus (TMV). The compounds 3l and 3n displayed good in vivo protection and curative effects against TMV with inhibitory rates of 60.1, 62.8% (protection) and 56.7, 53.6% (curative) at 0.5 mg/mL, respectively. To the best of our knowledge, this is the first report on the antiviral activity of chiral thioureas containing leucine and phosphonate moieties.