合成路线1

The cyclization of 4-benzoyloxycyclohexanone (I) with ethyl 2-bromomethylacrylate (II) and propylamine (III) in refluxing toluene gives ethyl 1-propyl-6-benzoyloxy-1,2,3,4,5,6,7,8-octahydroquinoline-3-carboxylate (IV), which is reduced with sodium cyanoborohydride in methanol yielding the corresponding decahydro derivative (V). Debenzoylation of (V) with NaOH in methanol affords the hydroxyquinoline (VI), which is oxidized with CrO3-pyr giving ethyl 1-propyl-6-oxodecahydroquinoline-3-carboxylate (VII). The reaction of (VII) with dimethylformamide dimethylacetal (VIII) in refluxing toluene yields ethyl 1-propyl-6-oxo-7-(dimethylaminomethylene)decahydroquinoline-3-carboxylate (IX), which is cyclized with hydrazine in ethanol affording ethyl 5-propyl-4,4a,5,6,7,8,8a,9-octahydro-2H-pyrazolo[3,4-g]quinoline-7-carboxylic acid (X). The reduction of (X) with LiAlH4 in THF gives the corresponding hydroxymethyl derivative (XI), which is esterified with methanesulfonyl chloride to the mesyl ester (XII). Finally, this compound is treated with methyl mercaptane and NaH in DMF.