合成路线1

4-Formylbenzonitrile (I) was converted to oxime (II) by treatment with hydroxylamine hydrochloride in pyridine-ethanol. Chlorination of the oxime with NaOCl, followed by dehydrohalogenation of the intermediate imidoyl chloride and dipolar cycloaddition to vinylacetic acid (III) produced the racemic isoxazoline (IV). The cyano group of (IV) was then converted to amidine (V) by formation of the corresponding imidate and subsequent treatment with methanolic ammonia. After protection of the amidine function of (V) as the Boc-derivative, ester hydrolysis employing LiOH yielded carboxylic acid (VI). Methyl 2-piperidine acetate (VIII) was obtained by catalytic hydrogenation of 2-pyridylacetic acid (VII) in the presence of MeOH and HCl. Coupling of acid (VI) with the racemic methyl 2-piperidineacetate (VIII) in the presence of O-(1H-benzotriazol-1-yl)-N,N,N',N'-tetramethyluronium tetrafluoborate (TBTU) furnished a diastereomeric mixture of amides (IX). Cleavage of the Boc group of (IX) by means of either trifluoroacetic acid or methanolic HCl provided amidine (X). Finally, basic hydolysis of the methyl ester of (X) gave rise to the title compound.