Silica-Bonded 2-Hydroxyethylammonium Acetate as an Efficient and Recyclable Catalyst for the Synthesis of 2-Amino-4H-chromen-4-yl Phosphonates and β-Phosphonomalonates

PMDTA-catalyzed multicomponent synthesis and biological activity of 2-amino-4H-chromenes containing a phosphonate or phosphine oxide moiety

A new approach for the preparation of (2-amino-3-cyano-4H-chromen-4-yl)phosphonate derivatives is described. The multicomponent reaction of salicylaldehydes, malononitrile and dialkyl phosphites catalyzed by pentamethyldiethylenetriamine (PMDTA) provided the bicyclic derivatives in high yields. The method developed did not require chromatographic separation, since the products could be recovered from the reaction mixture by simple filtration. Our approach made also possible condensation with secondary phosphine oxides, and this reaction has not been previously reported in the literature. The crystal structures of five derivatives were studied by single-crystal XRD analysis. The in vitro cytotoxicity on different cell lines and the antibacterial activity of the (2-amino-4H-chromen-4-yl)phosphonates synthesized were also explored. According to the IC50 values determined, several derivatives showed moderate or promising activity against mouse fibroblast (NIH/3T3) and human promyelocytic leukemia (HL-60) cells. Furthermore, three (2-amino-3-cyano-4H-chromen-4-yl)phosphine oxides were active against selected Gram-positive bacteria.

Catalyst-Free [4+2] Cycloaddition of Ynamides with 2-Halomethyl Phenols To Construct 2-Amino-4H-Chromenes and α-Halo Enamides Simultaneously

We report the development of a facile protocol for the [4+2] cycloaddition of ynamides and 2-halomethyl phenols to afford the corresponding 2-amino-4H-chromenes and α-halo enamides under catalyst-free conditions. The reaction proceeds under mild conditions and exhibits good tolerance toward various functional groups and generates high yields. The plausible mechanism involves the formation of an active intermediate keteniminium as well as o-methylene quinone.

Ionic liquids grafted onto graphene oxide as a new multifunctional heterogeneous catalyst and its application in the one-pot multi-component synthesis of hexahydroquinolines

The synergistic effect of ionic liquids and carboxylic acids in the reaction mechanism improved the catalytic activity of supported ILs.

Multicomponent reactions: A simple and efficient route to heterocyclic phosphonates

Multicomponent reactions (MCRs) are one of the most important processes for the preparation of highly functionalized organic compounds in modern synthetic chemistry. As shown in this review, they play an important role in organophosphorus chemistry where phosphorus reagents are used as substrates for the synthesis of a wide range of phosphorylated heterocycles. In this article, an overview about multicomponent reactions used for the synthesis of heterocyclic compounds bearing a phosphonate group on the ring is given.

Pyridine-grafted graphene oxide: a reusable acid–base bifunctional catalyst for the one-pot synthesis of β-phosphonomalonates via a cascade Knoevenagel–phospha Michael addition reaction in water

Py–GO as a new acid–base bifunctional catalyst was synthesized and employed for the one-pot synthesis of β-phosphonomalonates in water.

K2CO3-mediated synthesis of functionalised 4-substituted-2-amino-3-cyano-4H-chromenes via Michael-cyclization reactions

An efficient approach for the synthesis of functionalized 4-substituted-2-amino-3-cyano-4H-chromenes moderate to high yields (up to 98%) has been achieved via a tandem K2CO3 catalyzed conjugate addition-cyclization reaction of malononitrile and a range of Knoevenagel adducts previously formed from oxindole, pyrazolone, nitromethane, N,N-dimethylbarbituric acid or indanedione. This methodology differs from the previous classical methods in its simplicity and ready availability of the catalyst.

Inorganic base catalyzed synthesis of (2-amino-3-cyano-4H-chromene-4-yl) phosphonate derivatives via multi-component reaction under mild and efficient conditions

Various phosphonate derivatives were synthesized in good to excellent yields by condensation of substituted salicylaldehydes, malononitrile and phosphites using anhydrous LiOH as a catalyst under mild conditions.