Aqueous microwave-assisted DMAP catalyzed synthesis of β-phosphonomalonates and 2-amino-4H-chromen-4-ylphosphonates via a domino Knoevenagel-phospha-Michael reaction

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.

4-(Dimethylamino)pyridine as Multivalent Catalyst in Organic Synthesis

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DMAP as a new efficient catalyst for the one-pot synthesis of condensed phthalazines

A new, convenient, and efficient method for the synthesis of 1H-pyrazolo[1,2-b]phthalazine-5,10-diones is developed starting from phthalhydrazide, aromatic aldehydes, and malononitrile using 4-N,N-dimethylaminopyridin as catalyst. This modified route provides much higher yields and a simple work-up procedure of products. Also this methodology is of interest due to the use of ethanol as a solvent without use of any toxic metals as catalyst, thus minimizing the cost, the operational hazards, and environmental pollution.