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31.
Certain phenols and naphtols were nitrated regioselectively with NaNO2 in the presence of KHSO4 at 50 °C in high yields. 相似文献
32.
α‐Amino nitriles are synthesized by the three‐component coupling reaction of aldehydes, amines and trimethylsilyl cyanide using FeCl3 as a solid acid catalyst, under solvent‐free conditions in good yields. The catalyst was recovered by simple filtration and was recycled in subsequent reactions. 相似文献
33.
Melamine trisulfunic acid is employed as a recyclable catalyst for the condensation reaction of aromatic aldehydes with 3‐methyl‐l‐phenyl‐2‐pyrazolin‐5‐one. This condensation reaction was performed in ethanol under refluxing conditions giving 4,4′‐(arylmethylene)‐bis‐(3‐methyl‐1‐phenyl‐1H‐pyrazol‐5‐ols) in 80‐96% yields. 相似文献
34.
A new and convenient method for the synthesis of biscoumarins based on the condensation of 4‐hydroxycoumarin and aromatic aldehydes in the presence of Mohr's salt hexahydrate (ferrous ammonium sulfate hexahydrate) as a novel catalyst on water is developed. This method has advantages such as the use of inexpensive and available reagent, avoidance of organic solvents, short reaction times, and high product yields. 相似文献
35.
The one-pot synthesis of spirooxindoles via three-component reaction of urea, isatin, and 1,3-dicarbonyl compounds in the presence of a catalytic amount of p-toluenesulfonic acid in acetonitrile has been carried out.