Example 12 Preparation of 2-(3,4-dihydroxybenzylidene)malononitrile: A mixture of 3,4-bis(methoxymethoxy)benzaldehyde (1.0 mmol), malononitrile (1.0 mmol), and NaOH (2 mg) in 5 mL of methanol was stirred for 24 hours at room temperature. After completion of the reaction, the solvent was removed by distillation under reduced pressure, the residue was dissolved in ethyl acetate and filtered through a silica gel pad. The filtrate was concentrated under reduced pressure to give the condensation product 2-(3,4-bis(methoxymethoxy)benzylidene)malononitrile as a yellow solid in 94% yield. The structure of the product was confirmed by 1H-NMR (300 MHz, CDCl3) and 13C-NMR (75 MHz, CDCl3): 1H-NMR δ (ppm) 7.86 (s, 1H), 7.68 (s, 1H), 7.53 (d, J = 9 Hz, 1H), 7.29 (d, J = 9 Hz, 1H), 5.35 (s, 2H), 5.28 (s, 2H), 5.28 (s, 2H). 5.28 (s, 2H), 3.54 (s, 3H), 3.53 (s, 3H); 13C-NMR δ (ppm) 168.1, 167.6, 149.8, 147.9, 134.6, 127.7, 126.1, 121.0, 118.8, 116.8, 96.0, 95.5, 56.9, 56.8.
![Propanedinitrile, 2-[[3,4-bis(methoxymethoxy)phenyl]methylene]-](/CAS/20210305/GIF/495411-89-7.gif)
