3-(7,8-Dimethoxy-1,3-dihydro-2H-3-benzazepin-2-on-3-yl)-propionaldehyde diethylacetal → 3-(7,8-dimethoxy-2-oxo-1,2-dihydro-3H-benzo[d]azepin-3-yl)propanal

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Reaction Conditions

Reaction Steps

Here, 3-(7,8-dimethoxy-1,3-dihydro-2H-3-benzazepin-2-on-3-yl)-propionaldehyde diethylacetal (3.5 g, 0.01 mol) is heated to 40° C. for 2 hours in 2N sulphuric acid (50 ml) and ethanol (50 ml). The alcohol is distilled off in vacuo, the residue is made alkaline with saturated potassium carbonate solution while cooling and extracted several times with ethyl acetate. The ethyl acetate extract is extracted twice with 5% sodium hydrogen sulfate solution. The bisulphate extract is acidified with concentrated hydrochloric acid and heated to 40° C. in vacuo for half an hour to eliminate the sulphur dioxide. Then saturated potassium carbonate solution is added, the mixture is extracted several times with methylene chloride, dried over magnesium sulphate and concentrated by evaporation.

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