Nano silica-bonded aminoethylpiperazine: a highly efficient and reusable heterogeneous catalyst for the synthesis of 4H-chromene and 12H-chromeno[2,3-d]pyrimidine derivatives
Heterogeneous ditopic ZnFe<sub>2</sub>O<sub>4</sub>catalyzed synthesis of 4H-pyrans: further conversion to 1,4-DHPs and report of functional group interconversion from amide to ester
Highly stable, environmentally benign ZnFe2O4 nanopowder was prepared, characterized and applied in the one-pot, three-component synthesis of 4H-pyrans in water. The ZnFe2O4 catalyst provides both acidic (Fe3+) and basic functionalities (O2−) as the reaction requires. The advantages of this method lie in its simplicity, cost effectiveness, environmental friendliness and easier scaling up for large scale synthesis. Water was exploited both as a reaction medium as well as a medium for synthesis of the catalyst. Moreover, water was the only byproduct. The present report puts forward an application of 4H-pyrans for the synthesis of 1,4-DHPs. This is the first attempt towards the synthesis of 4H-pyran-3-carboxylate from 4H-pyran-3-carboxamide. The corresponding functional group interconversion from amide to ester is rare in organic synthesis.
series of four 2‑amino‑3‑cyano‑4‑(3/4‑pyridyl)‑4H‑benzo[h]chromenes 2a-d and their dichlorido(p‑cymene)ruthenium(II) complexes 3a-d were tested for antiproliferative, vascular-disruptive, anti-angiogenic and DNA-binding activity. The coordination of the 4‑pyridyl‑4H‑naphthopyrans 2 to ruthenium led to complexes with pleiotropic effects. Unlike the free ligands 2a-d, their ruthenium complexes 3a-d showed
Triethanolamine-catalyzed expeditious and greener synthesis of 2-amino-4<i>H</i>
-chromenes
作者:Anilkumar S. Patel、Satishkumar D. Tala、Pankajkumar B. Nariya、Kartik D. Ladva、Naval P. Kapuriya
DOI:10.1002/jccs.201800203
日期:2019.3
Triethanolamine (TEOA), an inexpensive and eco‐friendly base, was used to efficiently catalyze the three‐component condensation reaction of heterocyclic/aromatic aldehyde, (α/β)‐naphthol, and malononitrile in water to give the corresponding substituted 2‐amino‐4H‐chromene derivatives with excellent yields.
Nano silica-bonded aminoethylpiperazine: a highly efficient and reusable heterogeneous catalyst for the synthesis of 4H-chromene and 12H-chromeno[2,3-d]pyrimidine derivatives
The reaction of nano silica with 3-chloropropyltrimethoxysilane followed by treatment with aminoethylpiperazine afforded nano silica-bonded aminoethylpiperazine (SB-APP). The structure of the synthesized SB-APP was characterized by FT-IR, TGA, BET, SEM and elemental analysis and identified as an efficient basic catalyst for the preparation of 2-amino-4H-chromenes and 12H-chromeno[2,3-d]pyrimidine derivatives. One-pot three-component reaction of phenols, aromatic aldehydes and malononitrile in the presence of the catalytic amounts of SB-APP afforded high yield of the corresponding 2-amino-4H-chromenes under mild reaction conditions. 12H-Chromeno[2,3-d]pyrimidines were successfully synthesized with reasonable yield by reacting the 2-amino-4H-chromenes with acetic anhydride in the same pot without purification of the corresponding chromene intermediates. All products were characterized by FT-IR, 1H NMR, 13C NMR and MS data. The catalyst was simply recovered from the reaction mixture and reused several times without significant loss of catalytic activity.
Microwave-assisted reactions: Three component process for the synthesis of 2-amino-2-chromenes under microwave heating
作者:Ramadan A. Mekheimer、Kamal U. Sadek
DOI:10.1002/jhet.13
日期:2009.3
A simple and efficient threecomponentprocess for the synthesis of 2-amino-2-chromenes utilizing the reaction of aryl aldehydes with active methylenes 2a,b and 1-naphthol in refluxing ethanol/piperidine under microwave-heating is described. J. Heterocyclic Chem., (2009).