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Reaction of α, β-unsaturated acid chlorides with primary enaminonitriles in presence of triethylamine affords, under very mild conditions, a simple and highly efficient regiospecific synthesis of polysubstituted 3,4-dihydro-2(1H)-pyridones. 相似文献
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An efficient synthesis of spinochalcone B and its analogues is achieved from readily available 2H‐pyran. 相似文献
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The three‐component reaction of aldehyde, malononitrile, and 4‐hydroxy coumarin has been efficiently performed in aqueous K2CO3 using a simple, clean, environmentally benign, novel procedure employing microwave irradiation. The observed yields and enhancement in reaction rates can be attributed to the uniform heating effect of microwave. The microwave‐accelerated reaction technique not only eliminates the use of external base and organic solvents but also requires only water in both the reaction step and workup, thus rendering the whole procedure into a truly ecofriendly protocol. 相似文献
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Debayan Sarkar 《Tetrahedron letters》2009,50(13):1431-4568
An expedient synthesis of the linear tetrahydrofurano benzopyran ring system of xyloketals is described involving an ortho ester Claisen rearrangement and an intramolecular cationic cyclisation. This strategy was applied for a short, stereocontrolled and high yield synthesis of the phytotoxic metabolite alboatrin. 相似文献
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《中国化学会会志》2003,50(2):273-278
Spiro[indole‐pyranoimidazoles] ( 5 ) and spiro[indole‐pyranobenzopyrans] ( 6 ) are readily synthesized in one step in 86–92 and 91–97% yields by the Michael condensation of 3‐dicyanomethylene‐2H‐indol‐2‐ones ( 2 ) with 1‐phenyl‐2‐thiohydantoin ( 3 ) and 4‐hydroxy‐2H‐1‐benzopyran‐2‐one ( 4 ), respectively, without using any catalyst under different reaction conditions (conventional heating and microwave irradiation using (a) polar solvents (b) neutral alumina/silica gel as inorganic solid support in solvent free conditions). 2 was synthesized in situ by the Knoevenagel condensation of indole‐2,3‐dione ( 1 ) and malononitrile in the absence of any catalyst. 100% conversion was observed in most cases on TLC which also showed the formation of a single product. The comparison between the various methods is established. 相似文献
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