合成路线1

Compound can be prepared in two ditferent ways both starting from 9,10-dibromo-9,10-dihydro-4H-benzo[4,5]cyclohepta[1,2-b]thiophene-4-one (II): 1) The reaction of compound (II) with refluxing methanol affords 9-bromo-10-methoxy-9,10-dihydro-4H-benzo[4,5]cyclohepta[1,2-b]thiophene-4-one (III), which is dehydrobrominated with KOH in refluxing methanol giving 10-methoxy-4H-benzo[4,5]cyclohepta[1,2-b]thiophene-4-one (IV). The condensation of compound (IV) with the magnesium derivative of 4-chloro-1-methylpiperidine (A) in THF yields 10-methoxy-4-(1-methyl-4-piperidyl)-4H-benzo[4,5]cyclohepta[1,2-b]thiophene-4-ol (V), which is finally dehydrated and demethylated with 3N HCl at 95-100 C. 2) The dehydrobromination of compound (II) with KOH in refluxing methanol affords 10-bromo-4H-benzo[4,5]cyclohepta[1,2-b]thiophene-4-one (VI), which is then condensed with the magnesium derivative of 4-chloro-1-methylpiperidine in THF giving 10-bromo-4-(1-methyl-4-piperidyl)-4H-benzo[4,5]cyclohepta[1,2-b]thiophene-4-ol (VII). This compound is dehydrated with 14% ethanolic HBr at 100 C giving 10-bromo-4-(1-methyl-4-piperidylidene)-4H-benzo[4,5]cyclohepta[1,2-b]thiophene (VIII) (2,3), which is finally hydrolyzed with 50% H2SO4 at 100 C. Compound (VIII) can be also be treated with piperidine and potassium terbutylate in dioxane at 130 C to give 10-piperidino-4-(1-methyl-4-piperidylidene)-4H-benzo[4,5]cyclohepta[1,2-b]thiophene (IX), which is finally hydrolyzed with refluxing 2N HCl. The starting material (II) is prepared by bromination of 9,10-dihydro-4H-benzo[4,5]cyclohepta[1,2-b]thiophene-4-one (I) with N-bromosuccinimide (B) and benzoyl peroxide in carbon tetrachloride.