反应详情

A solution of 24 g of the chromanone, 12 g of paraformaldehyde and 24 ml of piperidine in 300 ml of ethanol is heated at 70° for 3 hours and evaporated. The residue is taken up in dichloromethane/petroleum ether 1:1, the mixture is filtered through silica gel and evaporated, and 2,2-dimethyl-3-methylene-6-cyano-4-chromanone is obtained as an unstable oil.

1. customevaporated
2. filtrationthe mixture is filtered through silica gel
3. customevaporated