合成路线1

The acylation of 2-(4-chlorophenyl)ethylamine (I) with Ac2O in toluene gives the acetamide (II), which is cyclized with oxalyl chloride (III) in dichloromethane to yield the oxazolidinedione (IV). The cyclization of (IV) by means of FeCl3 in dichloromethane affords the oxazolo-isoquinoline (V), which is hydrolyzed with hot H2SO4 in methanol or AcOH to provide 7-chloro-1-methyl-3,4-dihydroisoquinoline (VI). The cyclization of (VI) with 3-(dimethylamino)-2-phenylacrylic acid ethyl ester (VII) in hot AcOH gives the benzoquinolizine (VIII), which is brominated with NBS in hot AcOH to yield the 1-bromo compound (IX). Finally, this compound is condensed with 3(S)-ethoxypyrrolidine (XIII) and carbon monoxide by means of Pd(OAc)2 dppp in hot acetonitrile to furnish the target acyl pyrrolidine compound. Alternatively, bromocompound (IX) is condensed with CO by means of Pd(OAc)2 dppp in hot DMSO to give the carboxylic acid (XI), which is treated with oxalyl chloride and DMAP in hot ethyl acetate to yield the corresponding acyl chloride (XII). Finally, this compound is condensed with 3(S)-ethoxypyrrolidine (XIII) by means of TEA in toluene. In a further method, the bromocompound (IX) is condensed with CO by means of Pd(OAc)2 dppp in hot methanol to yield the methyl ester (X), which is hydrolyzed with KOH in methanol/water to the already reported carboxylic acid (XI). A third method is also reported: The condensation of carboxylic acid (XI) with 3(S)-hydroxypyrrolidine (XIV) by means of NMM and HBTU in DMF gives the corresponding acyl pyrrolidine (XV), which is finally alkylated with ethyl iodide and KOH in DMF. The intermediate 3-(dimethylamino)-2-phenylacrylic acid ethyl ester (VII) has been obtained by condensation of 2-phenylacetic acid ethyl ester (XVI) with dimethylformamide diethylacetal (XVII) at 150 C.