Methylamine → 1-ethoxy-2-(2,6-difluorophenyl)-1-(N-methylimino)-ethane

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Reaction Steps

70.7 g (300 mmol) of 1-ethoxy-2-(2,6-difluorophenyl)-1-imino-ethane hydrochloride are added, while stirring, to a suspension of 30.9 g (300 mmol) of oxalic acid monoamide monohydrazide in 900 ml of N,N-dimethylformamide. The reaction mixture is heated to 80° and stirred at this temperature for 1 hour. During a period of 20 minutes 10.6 g of methylamine are passed into the resulting white suspension, which leads to the formation of a clear yellow solution. During a period of 1 hour a further 15.9 g of methylamine are passed into the solution. The solution is then stirred for another hour at 80°. The solvent is evaporated in vacuo. 400 ml of water are added to the residue. The aqueous mixture is stirred and the crystals are filtered off. 300 ml of water are added to the crystals. The mixture is again stirred and the crystals are filtered off. The crystals are dissolved in hot ethanol (ca. 500 ml). After the addition of activated charcoal the mixture is filtered over Hyflo. The filtrate is evaporated until crystallisation starts (ca. 230 ml of ethanol have to be distilled off). The mixture is then cooled in an ice bath. The crystals are filtered off and dried overnight in vacuo, yielding the product of example 1.

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