200 KGS OF Diethyl Formamido Malonate, USD172.0/KG 762.

In an effort to develop a green synthesis of coumarins, Ranu and Jana report the synthesis of five substituted coumarins via Knoevenagel condensation between o-hydroxy benzaldehydes and diethyl malonate or ethyl acetoacetate in the presence of the basic ionic liquid, 1-butyl-3-methylimidazolium hydroxide ([Bmim]OH), in the role both of catalyst and of reaction medium. The reaction was completed in room temperature in a short time (15-25 min) with high products’ yield (82%-92%) (fig. 4) while the ionic liquid could be recycled for five cycles without any significant loss in activity. After the five cycles of use, it was necessary to mix the recycled ionic liquid with 50% of fresh [32].

500 KGS OF Ethyl Amido Malonate, USD45.0/KG 782.

Subs. Azo - Coumarins; Azo - Schiff’s Bases; Pyridine; Condensation; Malonic Acid
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1000 KGS OF Methyl Malonic Acid, USD23.0/KG 845.

Valizadeh and his group, studied the appropriate conditions to synthesize 3-cyanocoumarins via Knoevenagel condensation of malononitrile with salicylaldehyde derivatives in the presence of the appropriate amount of catalyst ZrCl4 in the ionic liquid. They observed that 15 mol% of catalyst ZrCl4 in combination with 1-(n-butyl)-3-methylimidazolium tetrafluoroborate ([bmim]BF4) in room temperature and variable reaction time up to 40 min leads to the final products in good yields (42%-83%) (fig. 15). The advantages of this synthetic route is the eco-friendly character resulting from the ability to reuse the ionic liquid and conducting the reaction at room temperature [43].

Synthesize 3carboxycoumarin from diethyl malonate …

Shaabani et al. presented the use of 1,1,3,3-N,N,N',N'-tetramethylguanidine trifluoroacetate (TMGT) as a promoter for the synthesis of either coumarin-3-carboxylic acids or their ester derivatives under heating conditions or microwave irradiation. In Knoevenagel condensation the starting materials are the appropriate ortho-hydroxyaryl aldehyde and dialkyl malonate or Meldrum’s acid (fig. 21). The reaction was performed under solvent-free conditions by conventional heating at 120 oC in reaction time varying from 30 min-40 min and yield approximately 75%. The same reaction under microwave irradiation was completed in remarkably reduced reaction time 1-4 min with improved yields. As presented, ionic liquid could be reused four times without loss of activity. The combination of short reaction times under microwave irradiation with the recyclability of ionic liquid renders the developed methodology sufficiently environmentally friendly [49].

2-hydroxybenzaldehyde and dimethyl or diethyl malonate in the presence of …
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Recent advances in the study on synthesis of diethyl malonate

Valizadeh and Vaghefi presented the synthesis of 3-substituted coumarins via Knoevenagel reaction between the appropriate 2-hydroxybenzaldehyde and dimethyl or diethyl malonate in the presence of NaOMe as a catalyst and ionic liquid as a reaction medium. The optimum ionic liquid among the butyl methyl imidazolium salts, [bmim]X that was tested, was the 1-Butyl-3-methylimidazolium hexafluorophosphate [bmim]PF6. After optimization of reaction conditions, eleven coumarin compounds were synthesized in good yields and reaction time approximately 4 h (fig. 10). Moreover, it was shown that in the presence of triphenylphosphine (PPh3) the same coumarin derivatives were produced via Wittig reaction although in lower yields than those that were synthesized via Knoevenagel reaction.

arene O-substituted by diethyl malonate ..

In continuation of our previous work16-18 in the present study we report here the condensation reactions of 3-chloro-4-methoxy malon anilic acid (1a) with different substituted phenyl benzene-azo-salicylaldehydes (5a-5l) in the presence of pyridine as a condensing agent.

Diethyl Ethoxy Methylene Malonate for synthesis …