Trityl chloride → (S)-Hexahydro-6-[(triphenylmethyl)amino]-2,2-dimethyl-2H-azepine-7-one

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Reaction Steps

Hydrazine monohydrate (4.59 ml., 94.6 mmol.) was added to a solution of (S)-hexahydro-6-phthalimido-2,2-dimethyl-2H-azepine-7-one [preparred as described in Example 66(e), 19.98 g., 68.76 mmol.] in methanol (250 ml.) at room temperature under argon. The resulting mixture was stirred for 72 hours then filtered to remove the white precipitate. The volatiles were evaporated and the residue was dissolved in methylene chloride (560 ml.) and filtered to remove additional precipitate. To this filtrate was added triethylamine (13.3 ml., 96.21 mmol.) followed by triphenylchloromethane (20.65 g., 74.07 mmol.) and the resulting mixture was stirred for 1.5 hours. Additional triphenylchloromethane (958 mg., 3.44 mmol.) was added and the solvent was removed. The residue was partitioned between ethyl acetate and water. The organic layer was washed with brine, dried, filtered and concentrated to give a pale yellow foam. Following a crystallization from ethyl acetate and hexanes, 7.47 g. of title product was obtained as off-white crystals. The mother liquor was concentrated and crystallized from ethyl acetate and pentane to give a second crop (8.02 g.) of title product. The mother liquor was concentrated and the residue was flash chromatographed (E Merck silica gel) eluting with 4.5:5.5 ethyl acetate/hexanes to give 6.0 g of title compound as a white foam. The combined yield of title product was 21.49 g.; m.p. 139°-140° C.; [α]D =+43.4° (c=0.37, methylene chloride). TLC (2:3 hexane: ethyl acetate) Rf =0.63.

Provenance & Evidence