Methylamine → 7,8-Dimethoxy-3-[3-(methylamino)propyl]-1,3,4,5-tetrahydro-2H-3-benzazepin-2-one

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Reaction Conditions

Reaction Steps

Dissolve 50 g (0.18 mol) of 3-(7,8-dimethoxy-2-oxo-1,2,4,5-tetrahydro-benzo[d]azepin-3-yl)-propionaldehyde in 625 mL of methanol. Cool the resulting solution to 0° C. Then add 62.5 mL (0.81 mol; 4.5 equivalents) of 40% aqueous methylamine solution. Stir for one hour at 0° C., and then add 7.5 g (0.2 mol; 1.1 equivalents) of NaBH4. Stir for 30 minutes at 0° C. and then stir for 12 hours at ambient temperature. Evaporate off the methanol. The residue is taken up in aqueous hydrochloric acid solution (1N), washed with ethyl acetate and then the aqueous phase is brought to pH=8 by adding 20% sodium hydroxide solution and extracted with dichloromethane. The organic, phase is washed with water, dried over MgSO4, filtered and then evaporated to dryness to obtain 52 g of an oil.

Provenance & Evidence