the preparation of a series of 4 H -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-1 H -pyrazol-5(4 H )-one, and α-naphthol, respectively
ZnO/MgO containing ZnO nanoparticles as a highly effective heterogeneous base catalyst for the synthesis of 4H-pyrans and coumarins in [bmim]BF4
作者:H. Valizadeh、A. A. Azimi
DOI:10.1007/bf03246209
日期:2011.3
4H-Pyrans and coumarins were synthesized through one-pot reactions using ZnO/MgO solid sample containing ZnO nanoparticles as an efficient reusable catalyst in ionicliquid, [bmim]BF4. The catalyst is inexpensive and readily available, stable and storable, easily recycled and reused for several cycles with consistent activity. The procedure offers advantages in terms of high yields, short reaction
Efficient and green synthesis of 4<i>H</i>-pyran derivatives under ultrasound irradiation in the presence of K<sub>2</sub>CO<sub>3</sub> supported on acidic montmorillonite
作者:Dung Duc Pham、Giang Vo-Thanh、Thach Ngoc Le
DOI:10.1080/00397911.2017.1342844
日期:2017.9.17
ABSTRACT Acid-treated montmorillonite coating with K2CO3 is used as a catalyst for an efficient, rapid, one-pot synthesis of 4H-pyran derivatives in good yield under ultrasonic irradiation. The catalyst is environmentally benign, easy handling, nontoxic, stable in air, and inexpensive. GRAPHICAL ABSTRACT
Diethylene glycol-bis(3-methylimidazolium) dihydroxide as a dicationic ionic liquid catalyst for the synthesis of 4H-pyrane derivatives in aqueous medium
Diethylene glycol-bis(3-methylimidazolium) dihydroxide [DiEG(mim)(2)[OH](2) was prepared by the reaction between sodium hydroxide and diethylene glycol-bis(3-methylimidazolium) dibromide in aqueous ethanol at room temperature. This solid, quaternized ionic liquid was employed as a recyclable catalyst for the synthesis of 4H-pyrane derivatives in high yields from the three-component condensation reaction of malononitrile, aromatic aldehydes, and 1,3-dicarbonyls in water at room temperature. In addition, spiropyrane derivatives were synthesized from the reaction of isatin, malononitrile, and 1,3-dicarbonyls in water at reflux. The dicationic ionic liquid showed the same efficiency when used in consecutive reactions. (C) 2015 Elsevier Ltd. All rights reserved.
SHARANIN, YU. A.;PROMONENKOV, V. K.;SHARANINA, L. G., ZH. ORGAN. XIMII, 1982, 18, N 3, 625-629
作者:SHARANIN, YU. A.、PROMONENKOV, V. K.、SHARANINA, L. G.