合成路线1

The synthesis of baogongteng A has been published: The alkylation of 3-hydroxypyridine (I) with benzylbromide (II) gives 1-benzyl-3-hydropyridinium bromide (III), which is condensed with acrylonitrile (IV) by means of triethylamine at reflux temperature, yielding the bicyclic nitrile (V). The reduction of (V) with LiAlH4 gives the bicyclic hydroxy nitrile (VII), also obtained by stepwise reduction of (V) with H2 over Pd/C to (VI) and posterior reduction to (VII) with NaBH4. The protection of (VII) with trimethylsilyl chloride and triethylamine affords the silyloxy derivative (VIII), which is treated with methylmagnesium iodide to yield the acetyl derivative (IX). Oxidation of (IX) with m-chloroperbenzoic acid (MCPBA) in CHCl3 affords the acetoxy compound (X), which is finally debenzylated by hydrogenation with H2 and Pd/C in ethanol to give the free base (XI). This is then treated with benzoic acid.