Hydrolysis of physostigmine (I) with either NaOMe in ethanol or NaOBu in refluxing butanol (better yield) gives eseroline (II), which is condensed with phenyl isocyanate (III) by means of NaOMe in benzene, Na in benzene or Na in ether/benzene.

Hydrolysis of physostigmine (I) with either NaOMe in ethanol or NaOBu in refluxing butanol (better yield) gives eseroline (II), which is condensed with phenyl isocyanate (III) by means of NaOMe in benzene, Na in benzene or Na in ether/benzene.

The title carbamate was prepared by condensation of (-)-eseroline (I) with 4-isopropylphenyl isocyanate in Et2O in the presence of a catalytic amount of Na.

Condensation of 5-methoxy-1,3-dimethyl-2,3-dihydro-1H-indol-2-one (IV) with 2-chloroacetonitrile (XI) by means of a chiral phase transfer catalyst gives 2-(5-methoxy-1,3-dimethyl-2-oxo-2,3-dihydro-1H-indol-3-y)-acetonitrile, which is separated into enantiomers by chromatography. Reductocyclization of the (S)-enantiomer (XII) by means of Vitride affords (3aS)-N1-noresermethole (XIII), which is submitted to a reductive methylation to provide esermethole (X). O-demethylation of (X) by means of BBr3 or AlCl3 gives eseroline (II), which is finally condensed with phenyl isocyanate.

Hydrolysis of physostigmine (I) with either NaOMe in ethanol or NaOBu in refluxing butanol (better yield) gives eseroline (II), which is condensed with phenyl isocyanate (III) by means of NaOMe in benzene, Na in benzene or Na in ether/benzene.

Hydrolysis of physostigmine (I) with either NaOMe in ethanol or NaOBu in refluxing butanol (better yield) gives eseroline (II), which is condensed with phenyl isocyanate (III) by means of NaOMe in benzene, Na in benzene or Na in ether/benzene.

The title carbamate was prepared by condensation of (-)-eseroline (I) with 4-isopropylphenyl isocyanate in Et2O in the presence of a catalytic amount of Na.

Condensation of 5-methoxy-1,3-dimethyl-2,3-dihydro-1H-indol-2-one (IV) with 2-chloro-N,N-dimethylethyl-amine (V) by means of NaNH2 in toluene gives 3-[2-(di-methylamino)ethyl]-5-methoxy-1,3-dimethyl-2,3-dihydro-1H-indol-2-one (VI), which is reduced with Vitride (sodium bis(2-methoxyethoxy)aluminum dihydride) in toluene to yield the secondary alcohol (VII). Optical resolution of (VII) by means of (+)-2,3-di-O-(p-toluoyl)tartaric acid provides the (2S,3S)-diastereomer (VIII), which by reaction with methyl iodide in ethyl ether affords the ammonium salt (IX). Cyclization of compound (IX) by means of methylamine in acetonitrile provides esermethole (X), the methyl ether of eseroline, which is demethylated by means of BBr3 in dichloromethane to give eseroline (II). Finally, eseroline is condensed with phenyl isocyanate (VIII) by means of Na in ethyl ether.

Hydrolysis of physostigmine (I) with either NaOMe in ethanol or NaOBu in refluxing butanol (better yield) gives eseroline (II), which is condensed with phenyl isocyanate (III) by means of NaOMe in benzene, Na in benzene or Na in ether/benzene.

Hydrolysis of physostigmine (I) with either NaOMe in ethanol or NaOBu in refluxing butanol (better yield) gives eseroline (II), which is condensed with phenyl isocyanate (III) by means of NaOMe in benzene, Na in benzene or Na in ether/benzene.

Condensation of 5-methoxy-1,3-dimethyl-2,3-dihydro-1H-indol-2-one (IV) with 2-chloro-N,N-dimethylethyl-amine (V) by means of NaNH2 in toluene gives 3-[2-(di-methylamino)ethyl]-5-methoxy-1,3-dimethyl-2,3-dihydro-1H-indol-2-one (VI), which is reduced with Vitride (sodium bis(2-methoxyethoxy)aluminum dihydride) in toluene to yield the secondary alcohol (VII). Optical resolution of (VII) by means of (+)-2,3-di-O-(p-toluoyl)tartaric acid provides the (2S,3S)-diastereomer (VIII), which by reaction with methyl iodide in ethyl ether affords the ammonium salt (IX). Cyclization of compound (IX) by means of methylamine in acetonitrile provides esermethole (X), the methyl ether of eseroline, which is demethylated by means of BBr3 in dichloromethane to give eseroline (II). Finally, eseroline is condensed with phenyl isocyanate (VIII) by means of Na in ethyl ether.

Condensation of 5-methoxy-1,3-dimethyl-2,3-dihydro-1H-indol-2-one (IV) with 2-chloroacetonitrile (XI) by means of a chiral phase transfer catalyst gives 2-(5-methoxy-1,3-dimethyl-2-oxo-2,3-dihydro-1H-indol-3-y)-acetonitrile, which is separated into enantiomers by chromatography. Reductocyclization of the (S)-enantiomer (XII) by means of Vitride affords (3aS)-N1-noresermethole (XIII), which is submitted to a reductive methylation to provide esermethole (X). O-demethylation of (X) by means of BBr3 or AlCl3 gives eseroline (II), which is finally condensed with phenyl isocyanate.

Hydrolysis of physostigmine (I) with either NaOMe in ethanol or NaOBu in refluxing butanol (better yield) gives eseroline (II), which is condensed with phenyl isocyanate (III) by means of NaOMe in benzene, Na in benzene or Na in ether/benzene.

Hydrolysis of physostigmine (I) with either NaOMe in ethanol or NaOBu in refluxing butanol (better yield) gives eseroline (II), which is condensed with phenyl isocyanate (III) by means of NaOMe in benzene, Na in benzene or Na in ether/benzene.

The Friedel Crafts condensation of 6-methoxyindolin-2-one (I) with acetyl chloride and AlCl3 gives the 5-acetyl-6-methoxyindolin-2-one (II), which is treated with hydroxylamine and acetic anhydride to yield the O-acetyloxime (III). The cyclization of (III) affords the 3-methyl-6,7-dihydro-5H-isoxazolo[4,5-f]indol-6-one (IV), which is condensed with 4-(iodomethyl)piperidine-1-carboxylic acid tert-butyl ester (V) to provide the adduct (VI). Finally this compound is deprotected with TFA and benzylated with benzyl bromide (VII) to furnish the target compound.

Hydrolysis of physostigmine (I) with either NaOMe in ethanol or NaOBu in refluxing butanol (better yield) gives eseroline (II), which is condensed with phenyl isocyanate (III) by means of NaOMe in benzene, Na in benzene or Na in ether/benzene.