Silica‐bonded N‐propylpiperazine sodium n‐propionate(SBPPSP) was found to act as an efficient solid base for the preparation of a series of 4H‐benzo[b]pyran derivatives. SBPPSP was used as a recyclable heterogeneo...Silica‐bonded N‐propylpiperazine sodium n‐propionate(SBPPSP) was found to act as an efficient solid base for the preparation of a series of 4H‐benzo[b]pyran derivatives. SBPPSP was used as a recyclable heterogeneous solid base catalyst for the synthesis of 3,4‐dihydropyrano[c]chromenes, 2‐amino‐4H‐pyrans, 1,4‐dihydropyrano[2,3‐c]pyrazoles, and 2‐amino‐4H‐benzo[e]‐chromenes via the condensation reaction of dimedone, ethyl acetoacetate, 3‐methyl‐1‐phenyl‐1H‐pyrazol‐5(4H)‐ one, and α‐naphthol, respectively, with aromatic aldehydes and malononitrile in refluxing aqueous ethanol. The heterogeneous solid base showed similar efficiency when reused in consecutive reactions.展开更多
A simple and efficient procedure for the preparation of silica-bonded N-propylpiperazine sodium n-propionate(SBPPSP) by the hydrolysis of silica-bonded N-propylpiperazine methyl n-propionate(SBPPMP) in hydrochloric ac...A simple and efficient procedure for the preparation of silica-bonded N-propylpiperazine sodium n-propionate(SBPPSP) by the hydrolysis of silica-bonded N-propylpiperazine methyl n-propionate(SBPPMP) in hydrochloric acid(0.5 mol/L) followed by treatment with saturated sodium bicarbonate is described.The SBPPMP was obtained by the reaction of 3-silica-bonded N-propylpiperazine and methyl acrylate in methanol.SBPPSP was used as a recyclable basic catalyst for the synthesis of 3,4-dihydropyrano[c]chromenes by the reaction of aromatic aldehydes,malononitrile,and 4-hydroxycoumarin in aqueous ethanol(1:1 v/v) under reflux conditions.Biscoumarins were also obtained via condensation of aldehydes and 4-hydroxycoumarin in aqueous ethanol(1:1 v/v) under reflux conditions.The catalyst could be recycled several times without any additional treatment.展开更多
文摘Silica‐bonded N‐propylpiperazine sodium n‐propionate(SBPPSP) was found to act as an efficient solid base for the preparation of a series of 4H‐benzo[b]pyran derivatives. SBPPSP was used as a recyclable heterogeneous solid base catalyst for the synthesis of 3,4‐dihydropyrano[c]chromenes, 2‐amino‐4H‐pyrans, 1,4‐dihydropyrano[2,3‐c]pyrazoles, and 2‐amino‐4H‐benzo[e]‐chromenes via the condensation reaction of dimedone, ethyl acetoacetate, 3‐methyl‐1‐phenyl‐1H‐pyrazol‐5(4H)‐ one, and α‐naphthol, respectively, with aromatic aldehydes and malononitrile in refluxing aqueous ethanol. The heterogeneous solid base showed similar efficiency when reused in consecutive reactions.
基金Persian Gulf University Research Council for partial support of this work, PGU/FS/6-2/1390/694
文摘A simple and efficient procedure for the preparation of silica-bonded N-propylpiperazine sodium n-propionate(SBPPSP) by the hydrolysis of silica-bonded N-propylpiperazine methyl n-propionate(SBPPMP) in hydrochloric acid(0.5 mol/L) followed by treatment with saturated sodium bicarbonate is described.The SBPPMP was obtained by the reaction of 3-silica-bonded N-propylpiperazine and methyl acrylate in methanol.SBPPSP was used as a recyclable basic catalyst for the synthesis of 3,4-dihydropyrano[c]chromenes by the reaction of aromatic aldehydes,malononitrile,and 4-hydroxycoumarin in aqueous ethanol(1:1 v/v) under reflux conditions.Biscoumarins were also obtained via condensation of aldehydes and 4-hydroxycoumarin in aqueous ethanol(1:1 v/v) under reflux conditions.The catalyst could be recycled several times without any additional treatment.
