An open metal site metal–organic framework Cu(BDC) as a promising heterogeneous catalyst for the modified Friedländer reaction

•Cu(BDC) was used as catalyst for the modified Friedländer.•High conversions were achieved using catalytic amounts of the Cu(BDC).•The catalyst could be recovered and reused. A crystalline porous metal–organic framework Cu(BDC) was synthesized, and characterized by several techniques, including X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), Fourier transform infrared (FT-IR), atomic absorption spectrophotometry (AAS), hydrogen temperature-programmed reduction (H2-TPR), and nitrogen physisorption measurements. The Cu(BDC) exhibited high catalytic activity for the modified Friedländer transformation using 2-aminobenzyl alcohol as the starting material, thus offering advantages over the conventional Friedländer reaction in terms of avoiding the problems associated with the storage of the highly unstable 2-aminobenzaldehyde. Moreover, the Cu(BDC) could offer significantly higher catalytic activity than that of other Cu-MOFs such as Cu3(BTC)2, Cu(BPDC), and Cu2(BDC)2(DABCO). The catalyst could be recovered and reused several times without a significant degradation in catalytic activity. The modified Friedländer reaction could only occur in the presence of the solid Cu(BDC) with no contribution from leached active species.