Figure 1.

Chemical structures of zanamivir, guanidinoglycoside, and BS‐pyrimidine analogue and the synthetic strategy of BS‐pyrimidine derivatives. (a) Structures of zanamivir (1), guanidinoglycoside (2), and BS‐pyrimidine analogue (3). (b) Synthetic strategy of targeted compounds. Reagents and conditions: (i) K₂CO₃, DMF, different α‐bromo‐hydroxyl alkane protected by TBDMS, 12 hr, 80°C; (ii) TBAF, THF, 2 hr, room temperature (RT); (iii) 1,3‐di(t‐butyloxycarboryl)‐guanidine, DIAD, PPh₃, anhydrous THF, 5 hr, 0°C, RT; and (iv) TFA/DCM (1/10), 15 hr, 0°C, RT