Functionalized reduced graphene oxide as a useful and efficient base catalyst for the preparation of <scp> 4 <i>H</i> </scp> ‐pyran and pyran‐like tacrine compounds and their antibacterial activity

An easy, effective and eco-friendly one-pot process for the preparation of 4H-pyran compounds has been established by using a catalytic amount reduced graphene oxide functionalized with diethylenetriamine (rGO-DETA) in water under mild conditions. The catalyst was very this reaction provided desired products 1a–t good to high yields (87%–97%) short times. Moreover, rGO-DETA composite could be reused four cycles without an obvious decrease its performance. In next step, two pyran derivatives 1f 1h were used synthesize corresponding pyran-like tacrine 3f 3h via cyclohexanone, aluminum trichloride reflux 1,2-dichloroethane as solvent. Antibacterial activity several prepared assessed against Gram-positive Gram-negative bacteria well disk diffusion techniques. 1g 1s (2000 μg/ml) Micrococcus luteus bacterium recording zone inhibition 15 16 mm, respectively. 1m showed moderate antibacterial behavior both M. Serratia marcescens. Pyran-like analog (50 mg/ml) displayed towards Staphylococcus aureus S. marcescens zones 13 12 1j featured minimum inhibitory concentration value 39.06 μg/ml luteus, which is closest ampicillin.