合成路线1

Condensation of p-fluorobenzaldehyde (I) with propionic anhydride (II) by means of sodium propionate at 140 C affords p-fluoro-alpha-methylcinnamic acid (III), which is then hydrogenated over Pd/C in EtOH to provide p-fluoro-alpha-methylhydrocinnamic acid (IV). Derivative (IV) is subjected to cyclization by treatment with polyphosphoric acid (PPA) to give 6-fluoro-2-methylindanone (V), which is converted into 5-fluoro-2-methylindenyl-3-acetic acid (VII) by first condensation with cyanoacetic acid (VI) by means of acetic acid and ammonium acetate in refluxing toluene, followed by hydrolysis with KOH in hot ethanol. Condensation of derivative (VII) with p-methylthiobenzaldehyde (VIII) by means of sodium methoxide in hot MeOH affords 5-fluoro-2-methyl-1-[p-(methylsulfanyl)benzylidene]-3-indenyl acetic acid (IX), which is then oxidized in MeOH/acetone by means of an aqueous solution of sodium periodate to yield methylsulfinylbenzylidene derivative (X). Finally, the target product is obtained by further oxidation of (X) with H2O2 in the presence of sodium methoxide and sodium bicarbonate in MeOH/acetonitrile at -10 C.