Ethyl Acetate → 1,2,3,3a,8,8a-Hexahydro-5-(methyloxycarbonylamino)-1,3a,8-trimethylpyrrolo[2,3-b]indole

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Reaction Conditions

Reaction Steps

1,2,3,3a,8,8a-Hexahydro-5-nitro-1,3a,8-trimethylpyrrolo[2,3-b]indole (1.0 g) was dissolved in ethyl acetate (100 ml) and hydrogenated in a Parr apparatus at 45 psi using PtO2 (100 mg) as a catalyst. The reduction was complete within 2 hours. The reduction mixture was filtered directly into a nitrogen flushed flask. 4-Dimethylaminopyridine (50 mg) was added, the mixture was cooled to 0° C. and a solution of dimethylpyrocarbonate (0.54 g) in ethyl acetate (50 ml) was added over a period of 1 hour. The mixture was concentrated and purified by flash chromatography on silica gel (eluting with 15% MeOH/EtOAc). The pure fractions were concentrated to give 1,2,3,3a,8,8a-hexahydro-5-(methyloxycarbonylamino)-1,3a,8-trimethylpyrrolo[2,3-b]indole (0.4 g) and the oxalate salt was prepared by dissolving the free base in ether and a minimal amount of methanol and adding a solution of oxalic acid in ether.

Provenance & Evidence