The condensation of aromatic aldehydes with isopropylidene malonate or 5,5-dimethyl-1,3-cyclohexanedione is carried out by DMF as solvent without catalyst.
A protocol for the Knoevenagel condensation of aromatic aldehydes with methylene compounds catalyzed by task specifed ionic liquid 1,8-diazabicyclo[5.4.0]-undec-7-en-8-ium lactate under solvent-free conditions has bee...A protocol for the Knoevenagel condensation of aromatic aldehydes with methylene compounds catalyzed by task specifed ionic liquid 1,8-diazabicyclo[5.4.0]-undec-7-en-8-ium lactate under solvent-free conditions has been developed. The reactions proceed at ambient temperature and the work-up procedures are very simple. Good to excellent yields could be obtained. The ionic liuid could be simply prepared and recycled efficiently.展开更多
5-Alkenyl-2,2-butylidene-1,3-dioxane-4,6-diones were synthesized by the Knoevenagel condensation reaction of aromatic aldehydes with 2,2-butylidene-1,3-dioxane-4,6-dione using o-phthalimide-N-sulfonic acid as catalyst...5-Alkenyl-2,2-butylidene-1,3-dioxane-4,6-diones were synthesized by the Knoevenagel condensation reaction of aromatic aldehydes with 2,2-butylidene-1,3-dioxane-4,6-dione using o-phthalimide-N-sulfonic acid as catalyst, without solvent under ultrasonic irradiation. The present method has some notable advantages such as mild reaction conditions, short reaction times, less catalyst dosage and high yields with the green aspects by avoiding toxic catalysts and solvents. Further, the catalyst can be reused for five times without any noticeable decrease in the catalytic activity.展开更多
The knoevenagel condensation reaction of barbituric acid and aromatic aldehyde under ground and heated in solventless system was described. The reaction mechanism was also proposed. The structures of the products were...The knoevenagel condensation reaction of barbituric acid and aromatic aldehyde under ground and heated in solventless system was described. The reaction mechanism was also proposed. The structures of the products were identified by IR, 1H NMR, 13 C NMR and UV. 5 Alkylidene barbituric acid was the only product in the two reaction systems.展开更多
文摘The condensation of aromatic aldehydes with isopropylidene malonate or 5,5-dimethyl-1,3-cyclohexanedione is carried out by DMF as solvent without catalyst.
基金Supported by the National Natural Science Foundation of China(No.20776127)the National Key Technology Research and Development Program of China(No.2007BAI34B07)
文摘A protocol for the Knoevenagel condensation of aromatic aldehydes with methylene compounds catalyzed by task specifed ionic liquid 1,8-diazabicyclo[5.4.0]-undec-7-en-8-ium lactate under solvent-free conditions has been developed. The reactions proceed at ambient temperature and the work-up procedures are very simple. Good to excellent yields could be obtained. The ionic liuid could be simply prepared and recycled efficiently.
文摘5-Alkenyl-2,2-butylidene-1,3-dioxane-4,6-diones were synthesized by the Knoevenagel condensation reaction of aromatic aldehydes with 2,2-butylidene-1,3-dioxane-4,6-dione using o-phthalimide-N-sulfonic acid as catalyst, without solvent under ultrasonic irradiation. The present method has some notable advantages such as mild reaction conditions, short reaction times, less catalyst dosage and high yields with the green aspects by avoiding toxic catalysts and solvents. Further, the catalyst can be reused for five times without any noticeable decrease in the catalytic activity.
文摘The knoevenagel condensation reaction of barbituric acid and aromatic aldehyde under ground and heated in solventless system was described. The reaction mechanism was also proposed. The structures of the products were identified by IR, 1H NMR, 13 C NMR and UV. 5 Alkylidene barbituric acid was the only product in the two reaction systems.
