反应详情

Alternatively, compounds of Formula III can be prepared as shown in Schemes 3 and 4. Condensation of 3,5-dimethoxybenzaldehyde with ethyl cyanoacetate in the presence of a base such as piperidine produces the 3-(3,5-dimethoxyphenyl)-2-cyano-acrylic acid ethyl ester. Treatment of the ester with 3-methoxyphenol in the presence of NaH produces the 3-cyano-7-methoxy-4-(3,5-dimethoxyphenyl)-2-oxo-2H-chromene. Similarly, reaction of 3-(3-methoxy-phenyl)-2-cyano-acrylic acid ethyl ester with 4-hydroxyindole produces 3-cyano-4-(3-methoxyphenyl)-2-oxo-2H-pyrrolo[2,3-h]chromene.