Trifluoroacetic acid → Ammonia

Participants

Reaction Steps

The product of step 1 was treated with trifluoroacetic acid at 0° C. for 30 minutes. The mixture was evaporated under aspirator vacuum and the residue was partitioned between water and ethyl acetate. The phases were separated and the aqueous phase was mixed with dichloromethane. The pH of this mixture was adjusted to 12.00 by addition of 28% aqueous sodium hydroxide. The phases were separated and the organic phase was washed with half concentrated brine dried over sodium sulfate and evaporated. The residue was purified by chromatography on silica gel with methylenechloride:methanol:ammonia=90:10:1 to yield the title compound (3S,5R,8aR)-3,5-Dimethyl-1,3,5,6,7,8,8a,9-octahydro-2-oxa-4,4b,7-triaza-cyclopenta[b]fluorene as slightly yellow crystals m.p.: 90-91° C.

Provenance & Evidence