Synthesis of functionalized chromene and spirochromenes using l -proline-melamine as highly efficient and recyclable homogeneous catalyst at room temperature
commercially cheap l-proline and melamine for the synthesis of chromenes and spirochromenes (spirooxindoles) via multicomponent reactions at room temperature. Systematic studies were conducted in order to achieve desired reactivity and recyclability of the catalyst using various α-amino acids and aromatic amines as donor-acceptor pairs. Among the screened combinations, l-proline and melamine (3:1 ratio;
biologically active natural products and in synthetic chemistry and in the fields of medicinal, agrochemical, cosmetic, and pigment industries. In this work, piperidine was used as a base catalyst for the convenient synthesis of 1,4‐dihydropyrano[2,3‐c]pyrazole, 5,10‐dihydro‐4H‐benzo[g]chromene, and pyrazolo[1,2‐a] [1,2,4]triazole derivatives at ambient temperature. This methodology has several advantages
含氧杂环化合物Chromenes在具有生物活性的天然产物和合成化学以及医药,农业化学,化妆品和颜料工业领域中具有“特殊”地位。在这项工作中,哌啶被用作基础催化剂,可方便地合成1,4-二氢吡喃并[2,3- c ]吡唑,5,10-二氢-4- H-苯并[ g ]色烯和吡唑并[1, 2– a ] [1,2,4]三唑衍生物在环境温度下。该方法具有许多优点,包括使用容易获得且价格便宜的催化剂,反应时间短,产率高,后处理方便以及不需要柱色谱。
One-pot synthesis of 2-amino-3-cyano-4<i>H</i>-pyrans and pyran-annulated heterocycles using sodium citrate as an organo-salt based catalyst in aqueous ethanol
作者:Aiborlang Thongni、Pynskhemborlang T. Phanrang、Arup Dutta、Rishanlang Nongkhlaw
DOI:10.1080/00397911.2021.1998535
日期:2022.1.2
shorter reaction time, utilization of eco-friendly solvents, operational simplicity, mild reaction conditions, and maximum product yield. Moreover, the use of sodium citrate as an easily available, cheap and benign catalyst plays a pivotal role from a green perspective, considering its high recyclability and easy recovery. Therefore, this present methodology offers numerous possibilities in terms of large-scale
Abstract A series of substituted 4H-pyrans derivatives were synthesized by a one-pot, multi-component reaction of aromatic aldehydes, malononitrile, and pyrazolone derivatives or active methylene carbonyl compounds such as dimedone, in the presence of 1,3-dimethyl imidazolium dimethyl phosphate [DMImd-DMP] as a catalyst in aqueous ethanol. Recyclability of the catalyst, high yields, simple product
propanedinitrile (2), hydrazine hydrate (3) and ethyl acetoacetate (4) under solvent-free conditions. We report herein the use of the Brønsted acid ionic liquid (BAIL) triethylammonium hydrogen sulphate [Et3NH][HSO4] as catalyst for this multi-component synthesis. Compared with the available reaction methodology, this new method has consistent advantages, including excellent yields, a short reaction time