Condensation of dibenzosuberenone (I) with sodium 2-chloro-2,2-difluoroacetate (II) in diglyme at 165 C gives 10,11-(difluoromethano)benzosuberone (III), which is reduced with NaBH4 in THF/methanol to yield the corresponding syn-alcohol (IV). Reaction of alcohol (IV) with hot SOCl2 affords a mixture of the syn- and anti-chloro derivatives (V). This mixture (V) is treated with 1-for-mylpiperazine (VI) in refluxing acetonitrile to provide a mixture of syn- and anti-4-[10,11-(difluoromethano)dibenzosuber-5-yl]piperazine-1-carbaldehyde (VI), which is separated by chromatography. The desired anti-isomer (VII) is then treated with KOH in refluxing ethanol/water to give the piperazine derivative (VIII), which is finally condensed with 5-[2(R),3-epoxypropoxy]quinoline (IX) in refluxing isopranol. 5-[2(R),3-Epoxypropoxy]quinoline (IX) is obtained by reaction of 5-hydroxyquinoline (X) with (R)-glycidyl tosylate (XI) by means of NaH in DMF.
Reaction of alcohol (IV) with 48% HBr or with PBr3 affords the anti-bromo derivative (XII), which is condensed with pyrazine (XIII) in refluxing acetonitrile to give anti-1-[10,11-(difluoromethano)dibenzosuber-5-yl]pyrazinium bromide (XIV). Reduction of compound (XIV) with NaBH4 in ethyl acetate provides the piperazine derivative (VIII), which is finally condensed with 5-[2(R),3-epoxypropoxy]quinoline (IX) ?obtained by reaction of 5-hydroxyquinoline (X) with (R)-glycidyl 4-nitrobenzene- sulfonate (XV) by means of K2CO3 in DMF ?in hot ethanol.
Condensation of the anti-bromo derivative (XII) with piperazine (XVI) in refluxing acetonitrile provides 1-[10,11-(difluoromethano)dibenzosuber-5-yl]piperazine as a mixture of syn- and anti-isomers (XVII), which is separated by crystallization. Finally, the desired anti-isomer (VIII) is condensed with 5-[2(R),3-epoxypropoxy]quinoline (IX) in hot ethanol.