An efficient condensation of substituted salicylaldehyde and malononitrile catalyzed by lipase under microwave irradiation

Abstract

The present work illustrates the condensation of substituted salicylaldehyde and malononitrile catalyzed by lipase under microwave irradiation. The reaction obtains two different products by a delicate control of the substrate molar ratio and reaction time. This protocol has the advantages of high

Efficient promiscuous Knoevenagel condensation catalyzed by papain confined in Cu3(PO4)2 nanoflowers

“…Further, undesired side-reactions such as oligomerization may occur with relatively low reaction temperatures, and catalyst recovery is challenging. 6 As reported, the Knoevenagel condensation reaction 2,7,8 can take place on ethyl malonate (as substrate) bound to the Wang resin, however, product cleavage requires trifluoroacetic acid, leading to excess pollution when it afforded pure coumarin-3-carboxylic acid derivatives. 9 …”

“…Further, undesired side-reactions such as oligomerization may occur with relatively low reaction temperatures, and catalyst recovery is challenging. 6 As reported, the Knoevenagel condensation reaction 2,7,8 can take place on ethyl malonate (as substrate) bound to the Wang resin, however, product cleavage requires triuoroacetic acid, leading to excess pollution when it afforded pure coumarin-3-carboxylic acid derivatives. 9 To overcome those drawbacks mentioned above, numerous efforts have been made to develop better heterogeneous Knoevenagel catalysts, for example, metal-salt, nanoparticle catalyst, modied zeolites, ionic liquids or magnetic base analogues.…”

A Convenient One-pot Synthesis of Chromenyl Acrylates and Acrylonitriles

“…The reaction of salicylaldehydes with malononitrile revealed that a delicate control of solvent, temperature and ratio of reagents can determine the incorporation of one [12][13][14] , two, 15,16 or three 17 units of malononitrile in the final product (Figure 1, 1b, 2, 3b or 4) and also generate a dimeric product 15 (5) after stirring for one day in basic medium at room temperature.…”

Enzymatic Tandem Approach to Knoevenagel Condensation of Acetaldehyde with Acidic Methylene Compounds in Organic Media

“…It is well recognized that Knoevenagel condensations are generally carried out with aromatic aldehydes as substrates . Moreover, Wang et al reported a protocol based on lipase‐catalyzed condensation of substituted salicylaldehyde under microwave irradiation . To the best of our knowledge, only limited examples with aliphatic aldehydes have been reported, and all of them are limited to α,β‐unsaturated derivatives , .…”