合成路线1

The radical chlorination of 2-fluoro-4-methylpyridine (I) with NCS, benzoyl peroxide and acetic acid in refluxing acetonitrile gives a mixture of the starting material (I) and its mono (II) and dichloro (III) derivatives. This mixture of (I), (II) and (III) was treated with refluxing aqueous K2CO3 , which selectively hydrolyzes the monochloro derivative (II) to afford 2-fluoro-4-(hydroxymethyl)pyridine (IV). The compound (IV), which is easily separated from unreacted (I) and dichloro compound (III), is treated with methanesulfonyl chloride and TEA in ethyl acetate to provide the corresponding mesylate (V). The reaction of (V) with NaI in THF gives 2-fluoro-4-(iodomethyl)pyridine (VI), which is finally condensed with anthrone (VII) by means of lithium tert-butoxide in THF.