Figure 1.

Screening and synthesis of potential TLR2 inhibitors. (A) Cell-based screening of 2100 natural products and structure optimization of Taspine. (B) Total synthesis route of Taspine and derivatives. (1) Br₂, Fe, CH₃COONa, CH₃COOH, rt, 3 h, 70%; (2) BnBr, K₂CO₃, CH₃CH₂OH, rt, 4 h, 95%; (3) NaClO₂, H₂O₂, NaH₂PO₄, THF, H₂O, rt, 4 h, 90%; (4) CH₃COCl, CH₃OH, rf, 4 h, 80%; (5) Cu, anhyd DMF, 155 °C, 4 h, 70%; (6) Pd/C, H₂, THF, rt, 95%; (7) allyl bromide, K₂CO₃, DMF, 60 °C, 4 h, 43%; (8) 215 °C, 1 h, 70%; (9) OsO₄, NaIO₄, NMO, CH₂Cl₂, t-BuOH, H₂O, rt, 20 h, 40%; (10) dimethylamine, NaBH₃CN, CH₂Cl₂, 4 h, rt, 45%.