[C:1]([O:4][CH2:5][CH3:6])(=[O:3])[CH3:2].[Na].C(O[CH:11]=[C:12]([C:15]#[N:16])[C:13]#[N:14])C.[CH2:17]([OH:19])[CH3:18]>>[CH2:5]([O:4][C:1](=[O:3])[C:2]1[CH:11]=[C:12]([C:13]#[N:14])[C:15]([NH2:16])=[CH:18][C:17]=1[OH:19])[CH3:6]According to H.-W-. Schmidt et al. (Liebigs Ann. Chem. 1979, 2005-10), ethyl acetate (42 g, 323 mmol) is added to a solution of sodium (15 g, 23 mmol) in ethanol (4.0 l) and the mixture is stirred at room temperature for 30 minutes. Ethoxymethylene-malononitrile (40.6 g, 332 mmol) is added. After 30 minutes at 80° C., the reaction mixture is allowed to cool to room temperature and the resulting precipitate is filtered off with suction. The precipitate is dissolved using water, and the aqueous phase is acidified with concentrated hydrochloric acid and the resulting precipitate is filtered off with suction again. After recrystallization from acetic acid, the crystals are filtered off with suction, washed with water and subsequently dried. The desired product is obtained in 29% yield (21.5 g).
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