合成路线1

The reaction of cyclohexane-1,3-dione (I) with ammonia gives 3-amino-2-cyclohexen-1-one (II), which is cyclized with acrylic acid (III) by heating at 140 C yielding 1,2,3,4,5,6,7,8-octahydroquinoline-2,5-dione (IV). The dehydrogenation of (IV) by means of Pd/C in refluxing decaline affords 5-hydroxy-1,2,3,4-tetrahydroquinolin-2-one (V), which is condensed with epichlorohydrin (VI) by means of NaOMe or NaOH in methanol giving 5-(2,3-epoxypropoxy)-1,2,3,4-tetrahydroquinolin-2-one (VII). Finally, this compound is treated with tert-butylamine in methanol.

合成路线2

The monohydroxylated metabolite of NIK-247, (+)-9-amino-2,3,5,6,7,8-hexahydro-1H-cyclopenta[b]quinolin-8-ol (VI) has been synthesized as follows: The condensation of cyclohexane-1,3-dione (I) with 2-amino-1-cyclopentene-1-carbonitrile (II) by means of PPE gives 2-(3-oxo-1-cyclohexen-1-yl)-1-cyclopentene-1-carbonitrile (III), which is cyclized by means of BF3.Et2O to yield 9-amino-2,3,5,6,7,8-hexahydro-1H-cyclopenta[b]quinolin-8-one (IV). The reduction of (IV) with NaBH4 affords the corresponding racemic alcohol (V), which is submitted to optical resolution with (+)-di-p-toluyltartaric acid to give the desired compound (VI).

合成路线3

Condensation of 2-bromo-p-toluidine (I) with cyclohexane-1,3-dione (II) gives bromo enaminone (III), which is N-methylated with iodomethane and NaH, affording tertiary enaminone (IV). Treatment of (IV) with triphenylphosphine-palladium acetate complex/NHCO3 or palladium acetate in acetonitrile provides carbazolone (V). Treatment of carbazolone (V) with sodium metal in EtOH/dioxane (or sodium methoxide in 1,2-dimethoxyethane) and diethyl oxalate (VI) provides ethoxallyl derivative (VII), which is then converted into glyoxylic acid lactone (VIII). Coupling of (VIII) with 2-methylimidazol (IX) by means of benzyltriethylammonium chloride in CHCl3/H2O furnishes glyoxylate (X), which is converted into the target product by reaction again with 2-methylimidazol (IX) in dioxane and final treatment with HCl. Alternatively, glyoxylate (X) can be directly obtained from (VIII) by reaction with formaldehyde and 2-methylimidazol (IX) in dioxane.

合成路线4

Condensation of 2-iodoaniline (I) with cyclohexane-1,3-dione (II) at 120 C yields secondary amine (III), which is then methylated with iodomethane by means of sodium hydride in refluxing benzene to provide tertiary amine (IV). Treatment of (IV) with lithium diisopropylamide (LDA) and dimethylaminomethylene iodide (Eschenmoser's salt) (V) in THF yields dimethylaminomethyl derivative (VI), which is then coupled with 2-methylindole (VII) in DMF to give compound (VIII). Cyclization of cyclohexenone derivative (VIII) by means of palladium (II) acetate and triethylamine in acetonitrile provides carbazolone derivative (IX), which is finally converted into the desired hydrochloride salt by treatment with HCl.

合成路线5

The condensation of anthranilonitrile (I) with cyclohexane-1,3-dione (II) in the presence of p-toluenesulfonic acid (removal of water) gives the enaminoketone (III). Cyclization of (III) in the presence of K2CO3 and CuCl yields the aminoketone (IV), which is then reduced with LiAlH4.

合成路线6

The reaction of 1-indanone (I) with sodium azide in acetic acid/sulfuric acid gives the tetrahydroquinolone (II), which is reduced with LiAlH4 in THF, yielding the tetrahydroquinoline (III). The reaction of (III) with NaNO2 and sulfuric acid afords the N-nitroso derivative (IV), which is reduced wiith LiAlH4 in THF to the N-amino compound (V). The reaction of (V) with cyclohexane-1,3-dione (VI) gives the monohydrazone (VII), which is cyclized by means of HCl in refluxing acetic acid, yielding the tetracyclic compound (VIII). The reaction of (VIII) with dimethylamine and paraformaldehyde in hot acetic acid provides compound (IX), which is treated with 2-methylimidazole (X) in refluxing water to afford racemic cilansetron (XI). Finally, this racemate is submitted to optical resolution with di-p-toluyl-D-tartaric acid or D-pyroglutamic acid.

合成路线7

The reaction of trifluoroacetoacetic acid ethyl ester (I) with (?)-isoborneol (II) at 130 C gives the corresponding isobornyl ester (III), which is condensed with cyclohexane-1,3-dione (IV) and 3-cyanobenzaldehyde (V) by means of ammonium acetate in refluxing ethanol to yield the octahydroquinolone (VI). The hydrolysis of the ester group of (VI), with simultaneous dehydration by means of TsOH in refluxing toluene affords 4-(3-cyanophenyl)-5-oxo-2-(trifluoromethyl)-1,4,5,6,7,8-hexahydroquinoline-3-carboxylic acid (VII) as a racemic mixture. Optical resolution of (VII) through the diastereomeric salt with 1(S)-phenylethylamine (VIII) in toluene/butanol provides the desired isomer (IX), which is finally decarboxylated in N-methyl-2-pyrrolidone at 210 C to furnish the target hexahydroquinolone.

合成路线8

The condensation of 3-cyanobenzaldehyde (I) with trifluoroacetone (II) in piperidine gives 3-(4,4,4-trifluoro-3-oxo-2-butenyl)benzonitrile (III). The condensation of cyclohexane-1,3-dione (IV) with 1(R)-phenylethylamine (V) in refluxing toluene or THF yields the secondary enamine (VI), which is condensed with benzonitrile (III) by means of Tms-Cl in hot acetonitrile to afford the chiral adduct (VII). The cyclization of (VII) by means of NH3 in hot acetonitrile provides the chiral octahydroquinolone (VIII), which is finally dehydrated by means of TFA, MsOH, TsOH or HCl in refluxing acetonitrile to give the target hexahydroquinolone.

合成路线9

The condensation of trifluoroacetoacetic acid ethyl ester (I) with cyclohexane-1,3-dione (II) and 3-cyanobenzaldehyde (III) by means of ammonium acetate in refluxing ethanol gives the octahydroquinolone (IV), which is hydrolyzed at its ester group by means of LiOH in hot ethanol/water to yield the corresponding carboxylic acid (V). Finally, this compound is dehydrated by means of TsOH in refluxing toluene to afford the target intermediate (rac)-4-(3-cyanophenyl)-5-oxo-2-(trifluoromethyl)-1,4,5,6,7,8-hexahydroquinoline-3-carboxylic acid (VI).

合成路线10

1,3-Cyclohexanedione (I) was brominated in cold water, and the resulting 2-bromo-1,3-cyclohexanedione (II) was condensed with 2-aminopyridine (III) in boiling EtOH to afford the dihydropyridobenzimidazolone (IV). Further bromination in concentrated HBr at 70 C gave bromoketone (V), which was finally condensed with thiourea (VI) in EtOH to yield the target tetracyclic compound.

合成路线11

By condensation of substituted nicotinamide (VI) with the carbazolyoxymethyl-oxirane (XII) in hot methanol/water. The intermediates the nicotinamide (VI) and the oxirane (XII) have been obtained as follows: 1.- Nicotinamide (VI): The reaction of 4-hydroxybenzyl alcohol (I) with 2-nitropropane (II) by means of potassium tert-butoxide in hot diglyme gives 4-(2-methyl-2-nitropropyl)phenol (III), which is reduced to the corresponding amino derivative (IV) with H2 over Pd/C in methanol/ethanol/acetic acid. Finally, this compound is condensed with 6-chloronicotinamide (V) by means of K2CO3 in dimethylacetamide/isooctane. 2.- Oxirane (XII): The reaction of phenylhydrazine (VII) with cyclohexane-1,3-dione (VIII) by means of NaHCO3 in isopropanol/water gives the monohydrazone (IX), which is cyclized with hotpolyphosphoric acid yielding the 4-hydroxycarbazole (X). Finally, this compound is condensed with the glycidyl 3-nitrophenylsulfonate (XI) by means of K2CO3 in refluxing acetone.

合成路线12

Mannich reaction of 1,3-cyclohexanedione (I) with paraformaldehyde and dipropylamine affords intermediate (II) which, without isolation is condensed with acetone under Robinson annulation conditions, to produce the bicyclic amino ketone (III). Enamine reduction in (III) using NaBH3CN in AcOH gives a racemic amine, which is resolved via formation of the corresponding diastereoisomeric salts with (-)-ditoluyltartaric acid, and finally isolated as the hydrochloride salt.

合成路线13

The chlorination of cyclohexane-1,3-dione (I) with chloramine T in acetonitrile gives 2-chlorocyclohexane-1,3-dione (II), which is finally condensed with cyclopropanecarbonyl chloride (III) by means of potassium tert-butoxide in THF to yield the target cyclohexenyl ester.

合成路线14

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合成路线16