Synthesis of Imidazole and Theophylline Derivatives Incorporating Pyrimidine‐Fused Heterocycles Using Magnetic Nanoparticles‐Supported Tungstic Acid (MNP‐TA) Catalyst

Abstract

In the current study, divers pyrimidine‐fused heterocycles containing an imidazole, benzimidazole, or theophylline moieties were synthesized. For the synthesis of this category of compounds, first, some new bromo‐substituted aldehydes (BSAs) were synthesized using reaction of 4‐hydroxybenzaldehyde and dibromides. Then, BSAs were reacted with imidazole, benzimidazole, and theophylline in order to synthesize corresponding heterocyclic‐substituted aldehydes (HSAs). Finally, the synthesized HSAs underwent in a multi‐components reaction with barbituric acids, amines, and dimedone in the presence of magnetic nanoparticles‐supported tungstic acid (MNP‐TA) catalyst in order to synthesis target products in good to excellent yields. The MNP‐TA was reusable using an external magnetic field and providing a clean and efficient reaction conditions for efficient synthesis of this class of compounds.

Recent Synthetic Approaches Towards Biologically Potent Derivatives/Analogues of Theophylline

“…Keeping these views in considerations, Divar et al . in 2017 synthesized few novel pyrimidine‐fused heterocycles containing theophylline moiety, in multicomponent reaction pathway. In order to accomplish the required synthesis, first of all, theophylline‐based aldehyde 276 was synthesized in 75% yield by reacting 4‐hydroxy benzaldehyde with dibromide 201 in the presence of potassium carbonate, tetra ‐butyl ammonium bromide, and MeCN followed by subsequent treatment with theophylline 4 .…”

l-Cysteine-functionalized magnetic nanoparticles (LCMNP): as a magnetic reusable organocatalyst for one-pot synthesis of 9-(1H-indol-3-yl) xanthen-4-(9H)-ones

“…In the structure of this catalyst, system l-cysteine moieties were chemically grafted to the surface of magnetic nanoparticles, creating efficient amino acid-based catalytic sites to be used in organic reactions. In this study and in continuation of over previous works on magnetic nanoparticle-based catalyst systems [47][48][49][50][51][52][53][54], we would like to show the catalytic applicability of this LCMNP in another MCR for efficient synthesis of a class of xanthene derivatives.…”

A practical one‐pot three‐component procedure for preparation of 3a,8a‐dihydroxyindeno[1,2‐d]imidazole derivatives in aqueous ethanol

“…Imidazole and its derivatives have broad therapeutic applications, and incorporated into many important biologically and pharmaceutically active molecules . Their biological activities could also be improved if they joined to other heterocyclic compounds . They have also been widely studied in the field of material science as moderate electron‐transporting materials employed in high‐performance photoelectric devices .…”

“…[15,16] Their biological activities could also be improved if they joined to other heterocyclic compounds. [17] They have also been widely studied in the field of material science as moderate electron-transporting materials employed in highperformance photoelectric devices. [18,19] The widespread use of imidazole derivatives in the synthesis of various chemically [20][21][22] and industrially significant ionic liquids [23,24] is quite clear.…”