合成路线1

2) By reaction of 8-chloro-6,11-dihydro-5H-benzo[5,6]cyclohepta[1,2-b]pyridin-11-one (III) with the Grignard reagent (IV) to give the tertiary carbinol (V), which is dehydrated with 85% H2SO4 affording 8-chloro-11-piperidinylidene derivative (VI). Finally, cornpound (VI) is treated with ethyl chloroformate (II) in toluene.

合成路线2

Alcoholysis of 3-methylpyridine-2-carbonitrile (I) with hot tert-butanol and H2SO4 gives the N-tert-butylcarboxamide (II), which is alkylated with 3-chlorobenzyl chloride (III) and BuLi in THF, yielding N-tert-butyl-3-[2-(3-chlorophenyl)ethyl]pyridine-2-carboxamide (IV). The reaction of (IV) with refluxing POCl3 and then with NaOH affords the corresponding nitrile (V), which is condensed with 1-methylpiperidin-4-ylmagnesium chloride (VI) in THF to give the ketone (VII). Cyclization of (VII) by means of either BF3 in HF or trifluoromethanesulfonic acid yields 8-chloro-11-(1-methylpiperidin-4-ylidene)-6,11-dihydro-5H-benzo[5,6]cyclohepta[1,2-b]pyridine (VIII), which is reacted with cyanogen bromide in benzene to give the N-cyano compound (IX). Finally, this compound is treated with HCl in refluxing acetic acid/water. Alternatively, 8-chloro-11-(1-methylpiperidin-4-ylidene)-6,11-dihydro-5H-benzo[5,6]cyclohepta[1,2-b]pyridine (VIII) is treated with ethyl chloroformate in hot toluene, affording the carbamate (X) (2), which is finally decarboxylated with KOH or NaOH in refluxing ethanol/water.

合成路线3

Condensation of ethyl nicotinate (XI) with 3-chlorophenylacetonitrile (XII) by means of sodium ethoxide in ethanol gives 2-(3-chlorophenyl)-3-oxo-3-(3-pyridyl)propionitrile (XIII), which by refluxing with concentrated HBr yields 2-(3-chlorophenyl)-1-(3-pyridyl)ethanone (XIV). The reduction of (XIV) with hydrazine hydrate and NaOH in diethylene glycol at 235-40 C affords 3-(2-phenylethyl) pyridine (XV), which is oxidized with H2O2 in hot acetic acid to provide the corresponding N-oxide (XVI). Reaction of (XVI) with NaCN and dimethyl sulfate in water affords the previously described 3-(2-phenylethyl)pyridine-2-carbonitrile (V), which can be worked up as previously described or cyclized with polyphosphoric acid (PPA) at 180 C to give 8-chloro-6,11-dihydro-5H-benzo[5,6]cyclohepta[1,2-b]pyridin-11-one (XVII). The condensation of (XVII) with 1-methylpiperidin-4-ylmagnesium chloride (VI) in THF yields the corresponding carbinol (XVIII), which is dehydrated with PPA at 170 C to afford the previously reported 8-chloro-11-(1-methylpiperidin-4-ylidene)-6,11-dihydro-5H-benzo[5,6]cyclohepta[1,2-b]pyridine (VIII).

合成路线4

N-tert-Butyl-3-methyl-2-pyridinecarboxamide (I) was treated with two equivalents of butyllithium at -40 C, and the resulting dianion was C-alkylated with 3-chlorobenzyl chloride (II) to provide the phenetylpyridine (III). Further refluxing with phosphoryl chloride afforded nitrile (IV), which was condensed with the piperidinyl Grignard reagent (V) to yield, after hydrolysis, ketone (VI). Acid-catalyzed cyclization of ketone (VI) produced the tricyclic compound (VII). Demethylation was then accomplished by conversion to the ethyl carbamate (VIII) by treatment with ethyl chloroformate, followed by hydrolysis to the N-unsubstituted piperidine (IX). Finally, acetylation of (IX) in the presence of pyridine provided the target amide.

合成路线5