Example 8 Synthesis of 4-(2-guanidinothiazol-4-yl)phenyl 4-cyclopropyl benzoate (13f) Procedure:(a) Preparation of 4-cyclopropyl benzoate. Coumaric acid (2.63 g, 18.74 mmol) was mixed with cyclopropyl acetylene (1.24 g, 18.74 mmol) in diethylene glycol dimethyl ether and the reaction mixture was refluxed for 36 hours. After completion of the reaction, it was cooled to room temperature and the solvent was removed by distillation under reduced pressure. The resulting crude product was recrystallized in ethanol (EtOH) to give 1.26 g of 4-cyclopropylbenzoic acid in 42% yield. The product was characterized as follows: 1HNMR (DMSO-d6): δ7.81 (d, J=8.4 Hz, 2H), 7.16 (d, J=8.4 Hz, 2H), 1.97 (sept, J=5.1 Hz, 1H), 1.01 (m, 2H), 0.74 (m, 2H). 13CNMR (DMSO-d6): δ167.24 ,149.51,129.32,127.65,125.19,15.25,10.37.
