合成路线1

The reaction of 6-bromo-1,2,3,4-tetrahydronaphthalen-2-one (I) with 1,3-bis(trimethylsilyloxy)propane (II) by means of trimethylsilyl trifluoromethanesulfonate in THF gives the propylene ketal (III), which is treated with dimethyldisulfide and BuLi in THF yielding the methylsulfanyl derivative (IV). The hydrolysis of (IV) by means of HCl in THF affords 6-(methylsulfanyl)-1,2,3,4-tetrahydronaphthalen-2-one (V), which is condensed with 1(R)-phenyl ethylamine (VI) by means of p-toluenesulfonic acid in refluxing toluene giving the enamine (VII). The methylation of (VII) with lithium diisopropylamide and methyl iodide in THF yields the 1-methyldihydronaphthalene (VIII), which is cyclized with acryloyl anhydride (IX) in toluene affording the benzoquinoline derivative (X). The treatment of (X) with triethylsilane and trifluoroacetic acid to eliminate the chiral auxiliar gives intermediate (XI), which is methylated with methyllithium in THF yielding the N-methylbenzoquinoline (XII). The oxidation of (XII) with m-chloroperbenzoic acid (MCPBA) in dichloromethane affords the corresponding methylsulfinyl derivative (XIII), which by reaction with trifluoroacetic anhydride provides the trifluoroacetoxymethylsulfanyl derivative (XIV). Finally, this compound is condensed with 2-chloro-4-ethylbenzothiazole (XV) by means of tetrabutylammonium bisulfate (BNS) and NaBH4 in toluene/water.