A mild, simple and convenient procedure for the synthesis of spiro-oxindole heterocycles containing fused 4H-pyran ring and also bis-2-amino-4H-pyrans derivatives was described using C4(DABCO-SO3H)2·4Cl as a nano, efficient, cheap, and reusable catalyst under mild and homogeneous conditions.
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.
Glycerol is applied as a green, biodegradable and reusable promoting medium for one-pot three component synthesis of 4H-pyrans under catalyst-free conditions. A broad range of substrates including aromatic and heteroaromatic aldehydes, isatine derivatives, acenaphthenequinone and ninehydrine are condensed with carbonyl compounds possessing a reactive α-methylene group and alkylmalonates. All reactions are completed in short times, and the products are obtained in good to excellent yields. The reaction medium could be recycled and reused several times without any loss of efficiency.
Green multi-component domino reactions (MCRs)1–7 for the synthesis of fine chemicals have attracted much recent interest.8–9 Quinolines, spiro[4H-pyran-oxindoles] and xanthenes are reported as havi...
Copper(II) acetate monohydrate: an efficient and eco-friendly catalyst for the one-pot multi-component synthesis of biologically active spiropyrans and 1H-pyrazolo[1,2-b]phthalazine-5,10-dione derivatives under solvent-free conditions
natural and economical catalyst for the multi-component efficientsynthesis of biologically active spiro-4H-pyran derivatives and 1H-pyrazolo[1,2-b]phthalazine-5,10-dionederivatives with excellent yields and short reaction times. The most important advantages of this procedure are its mild, non-toxic and inexpensive catalyst, one-pot synthesis, environmentally benign nature, solvent-free conditions
摘要 我们已经研究了乙酸铜(II)一水合物作为温和的,对环境无害的,天然的和经济的催化剂,用于多组分有效合成生物活性spiro-4 H -pyran衍生物和1 H -pyrazolo的催化能力[1,2] -b] phthalazine-5,10-dione衍生物,具有优异的收率和较短的反应时间。该方法最重要的优点是其温和,无毒且便宜的催化剂,一锅合成,环境友好的性质,无溶剂条件,简单的操作程序和高效的条件。 图形概要