3.0 g (20 mmol) of 2-hydroxybenzaldehyde O-methyloxime are dissolved in 20 ml of methanol, and 3.6 g (20 mmol) of sodium methanolate (30% strength in methanol) are added. The mixture is refluxed for four hours and then concentrated. The residue is taken up in 100 ml of dimethylformamide, and 6.5 g (23 mmol) of methyl 2-bromomethylphenylglyoxylate O-methyloxime in 50 ml of dimethylformamide are added. The mixture is stirred at 100° C. for 5 hours, the solvent is stripped off, and the residue is taken up in ethyl acetate. The organic phase is washed with water, dried and concentrated. The residue is triturated with pentane to induce crystallization. 4.8 g (67% of theory) of the title compound are obtained in the form of colorless crystals (melting point 73°-76° C., compound no. 2).
