Synthesis and characterization of Fe3O4@SiO2-(CH2)3-NH-Asn-M(II) (Cu (II)/ Ni(II)/ Co(II)) and its catalytic application in the synthesis of chromeno-pyrazolo-phthalazine derivatives

Fe 3 O 4 @SiO 2 -(CH 2 ) 3 -NH-Asn-Cu(II) was synthesized via functionalization of synthesized Fe 3 O 4 with 3-aminopropyltriethoxysilane, asparagine, and Cu(OAc) 2 . The prepared magnetic nanocatalyst was used as a green and efficient catalyst for the synthesis of chromeno-pyrazolo[1,2- b ]phthalazine-6,9,14(7 H )-trione derivatives by reaction of aldehydes, phthalhydrazide, and 4-hydroxycoumarin in short reaction times and good yields. The magnetic nature of the catalyst led to easy and convenient separation by an external magnet and reused for 5 consecutive runs without significant loss inactivity. The structure of the catalyst was characterized by FT-IR, SEM, EDX, VSM analyses.