Diverse synthesis of pyrimido[1,2-a]benzimidazoles and imidazo[2,1-b]benzothiazoles via CuI-catalyzed decarboxylic multicomponent reactions of heterocyclic azoles, aldehydes and alkynecarboxylic acids

Synthesis of Substituted of Benzo[4,5]imidazo[1,2-a]pyrimidines through (3 + 2+1) Cyclization of 2-Aminobenzimidazole, Acetophenone, and N,N-Dimethylformamide as One-Carbon Synthon

An efficient method for the construction of benzo[4,5]imidazo[1,2-a]pyrimidines using N,N-dimethylformamide as a one-carbon source and 2-aminobenzimidazoles and acetophenone as substrates through a one-pot, three-component cascade reaction is described. Spectra investigations indicated the fluorescent properties of selected products, exhibiting quantum yields 0.07-0.16 with maxima absorption at 266-294 nm and emission at 472-546 nm.

Pyrimido[1,2-a]benzimidazoles as inhibitors of oncoproteins ubiquitin specific protease 5 and MYCN in the childhood cancer neuroblastoma

The MYCN oncogene and histone deacetylases (HDACs) are key driver genes in the childhood cancer, neuroblastoma. We recently described a novel pyridobenzimidazole analogue, SE486-11, which enhanced the therapeutic effectiveness of HDAC inhibitors by increasing MYCN ubiquitination through effects on the deubiquitinase, ubiquitin-specific protease 5 (USP5). Here we describe the synthesis of a novel series of pyrimido[1,2-a]benzimidazole derivatives, and an evaluation of their cytopathic effects against non-malignant and human neuroblastoma cell lines. Among the tested analogues, 4-(4-methoxyphenyl)benzo[4,5]imidazo[1,2-a]pyrimidine (3a) was the most active compound against neuroblastoma cells (IC50 ≤ 2 µM), with low cytotoxicity (IC50 ≥ 15 µM) to normal cells. We show compound 3a bound to USP5 protein (Kd = 0.47 µM) in vitro and synergistically enhanced the efficacy of HDAC inhibitors against neuroblastoma cells. Moreover, knockdown of USP5 and MYCN in treated neuroblastoma cells showed that both USP5 and MYCN expression was necessary for the cytopathic activity of compound 3a, thus providing a clinically relevant rationale for further development of this of pyrimido[1,2-a]benzimidazole.

Iron-catalyzed [3+2+1] annulation of 2-aminobenzimidazoles/3-aminopyrazoles and aromatic alkynes using N,N-dimethylaminoethanol as one carbon synthon for the synthesis of pyrimido[1,2-a]benzimidazoles and pyrimido[1,2-b]indazoles

A simple and efficient method for the synthesis of pyrimido[1,2-a]benzimidazoles and pyrimido[1,2-b]indazoles from 2-aminobenzimidazoles/3-aminoindazoles, alkynes and N,N-dimethylaminoethanol in a three-component [3+2+1] annulation catalyzed by FeCl3 has been established, where N,N-dimethylaminoethanol...

Pyrimido[1,2-a]benzimidazoles: synthesis and perspective of their pharmacological use

The review presents data on the synthesis as well as studies of biological activity of new derivatives of pyrimido[1,2-a]benzimidazoles published over the last decade. The bibliography of the review includes 136 sources.

α-Aminoazoles/azines: key reaction partners for multicomponent reactions

Aromatic α-aminoazaheterocycles are the focus of significant investigations and exploration by researchers owing to their key role in diverse biological and physiological processes. The existence of their derivatives in numerous drugs and alkaloids is due to their heterocyclic nitrogenous nature. Therefore, the synthesis of a structurally diverse range of their derivatives through simple and convenient methods represents a vital field of synthetic organic chemistry. Multicomponent reactions (MCRs) provide a platform to introduce desirable structure diversity and complexity into a molecule in a single operation with a significant reduction in the use of harmful organic waste, and hence have attracted particular attention as an excellent tool to access these derivatives. This review covers the advances made from 2010 to the beginning of 2020 in terms of the utilization of α-aminoazaheterocycles as synthetic precursors in MCRs.

Recent advances in multi-component reactions and their mechanistic insights: a triennium review

This review summarizes the recent developments in MCRs, incorporating different strategies along with their mechanistic aspects.

Recent advances in the synthesis of bridgehead (or ring-junction) nitrogen heterocycles via transition metal-catalyzed C–H bond activation and functionalization

An update on recent advances in the synthesis of bridgehead nitrogen fused heterocycles via transition metal-catalyzed C–H activation and functionalization is reported.

Synthesis of fused conjugated polymers containing imidazo[2,1-b]thiazole units by multicomponent one-pot polymerization

This work describes a method for synthesis of fused cyclic conjugated polymers possessing imidazo[2,1-b]thiazole units in the main chain by reaction of heteroclyclic diazoles, dialdehydes and terminal alkyne via multicomponent one-pot processes.