合成路线1

The condensation of the 2-chloroquinoline-3-methanol (I) with trimethylsilyl acetylene (II) by means of PdCl2(PPh3)2 and CuI in DMF gives 2-(trimethylsilylethynyl)quinoline-3-methanol (III), which is treated with PPh3, CBr4 and sodium azide to yield the azidomethyl derivative (IV). The reduction of (IV) with PPh3 in THF/water affords the aminomethyl compound (V), which is condensed with fumaric acid monoethyl ester (VI) by means of BOP in acetonitrile to provide the amide (VII). The cyclization of (VII) by means of Tms-Cl, DIEA and ZnCl2 in toluene at 180 C in a sealed tube gives the tetracyclic ester (VIII), which is treated with HBr in ethyl acetate to yield the intermediate ethyl ester (IX). The transesterification of (IX) catalyzed by H2SO4 in refluxing methanol affords the methyl ester (X), which is methylated with diazomethane to provide 2-methyl-1-oxo-1,11-dihydroindolizino[1,2-b]quinoline-3-carboxylic acid methyl ester (XI). The reduction of (XI) with LiBH4 in hot bis(2-methoxyethyl)ether gives the tetracyclic carbinol (XII), which is oxidized with DMSO in hot Ac2O to yield the carbaldehyde (XIII). Finally, this compound is treated with diazoethane in ethyl ether to afford the target propionyl derivative.