NiO‐Nanoparticles as green catalyst for an efficient synthesis of 4‐iminopyrido[1,2‐a]pyrimidine fluorophores via one pot cyclization of α‐aminonicotinonitrile

Abstract

AbstractUtilization of the nano‐catalysts in synthesis of applicable heterocycles is a key focus of research in green chemistry. The present work describes a one‐pot, three‐component, simple, and efficient approach for the synthesis of a new series of N‐bridged pyrido[1,2‐a]pyrimidine candidates utilizing NiO‐NPs as a green catalyst. α‐Aminopyridine 1 was synthesized from one‐pot condensation of 4‐chlorobenzaldehyde, chloroacetyl chloride, and malononitrile in the presence of ammonium acetate. α‐Aminopyridine 1 was condensed with a variety of aromatic or/heteroaromatic aldehydes and malononitrile in the presence of NiO‐NPs to afford pyrido[1,2‐a]pyrimidine derivatives in good yield (75–92%) and with simple purification. Mild reaction conditions, no‐column purification, and high yield of the products are evident features of such an approach, in addition to the high efficiency, cheap, soft, chemically stable, and readily available NiO‐NPs. The pyrido[1,2‐a]pyrimidine fluorophores 3c,d, i, and 3j have higher fluorescence wavelengths at (λflu.max = 460–480 nm) than the rest of compounds 3a,b, and 3e–h (λflu.max = 430–455 nm).