Diisopropylethylamine → 2-((Methoxy)(4-phenoxyphenyl)methylene)malononitrile

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Reaction Conditions

Reaction Steps

1,1-Dicyano-2-hydroxy-2-(4-phenoxyphenyl)ethene (Intermediate Z) (56.5 g) in 780 mL acetonitrile and 85 mL methanol was stirred under nitrogen at 0° C. while adding 52.5 mL diisopropylethylamine then 150 mL 2M-trimethylsilyldiazomethane in THF. After stirring for 2 days at 20° C., 2 g silica for chromatography was added: no further evolution of nitrogen was noted. The brown-red solution was evaporated in vacuo, the residue dissolved in ethyl acetate and washed well with water then brine, dried and evaporated. The residue was extracted with diethyl ether (3×250 mL), decanting from insoluble oil. Evaporation of the ether extracts gave 22.5 g of 1,1-Dicyano-2-methoxy-2-(4-phenoxyphenyl)ethene as a pale orange solid almost pure by t.l.c. (3:2 ethyl acetate:cyclohexane). The insoluble oil was purified by flash chromatography giving 15.0 g red-orange oil. Combined yield (63%) 1H NMR (DMSO-d6, 400 MHz) 7.71 (d, 2H), 7.48 (m, 2H), 7.29 (m, 1H), 7.16 (m, 4H), 3.93 (s, 3H).

Provenance & Evidence