An Efficient and Facile Method for the Synthesis of Benzimidazoisoquinoline Derivatives via a Multicomponent Reaction

Recent Advances in Heterocyclic Nanographenes and Other Polycyclic Heteroaromatic Compounds

This review surveys recent progress in the chemistry of polycyclic heteroaromatic molecules with a focus on structural diversity and synthetic methodology. The article covers literature published during the period of 2016-2020, providing an update to our first review of this topic (Chem. Rev. 2017, 117 (4), 3479-3716).

One-pot synthesis of natural-product inspired spiroindolines with anti-cancer activities

A post-Ugi/diastereoselective cascade reaction was developed to construct the spiroindoline scaffold through a 5-exo-dig indole cyclization and the intramolecular trapping of the spiro intermediate forming a quaternary carbon center.

Facile synthesis and biological evaluation of tryptamine-piperazine-2,5-dione conjugates as anticancer agents

A facile and efficient route to synthesize N-heterocyclic fused tryptamine-piperazine-2,5-dione conjugates was developed via a post-Ugi cascade reaction. The targeted compounds were prepared by means of a mild reaction and simple operation procedure, which could be applied to a broad scope of starting materials. Compound 6h was demonstrated to induce significant growth inhibition of AsPC-1 and SW1990 human pancreatic cancer cell lines (IC₅₀ = 6 ± 0.85 μM). Our protocol allows for the construction of a structurally diverse compound library and paves a new avenue for the discovery of pancreatic cancer drug candidates.

A series of tryptamine-piperazine-2,5-dione conjugates derivatives was designed and synthesized via Ugi cascade reaction. The discovery of compound 6h may provide a new avenue for pancreatic cancer drug discovery.

Catalyst-Free One-Pot Synthesis of Densely Substituted Pyrazole-Pyrazines as Anti-Colorectal Cancer Agents

The first catalyst-free post-Ugi cascade methodology was developed for expeditious access to structurally diverse and complex pyrazole-pyrazines in one-pot. This novel cascade reaction features an intramolecular N2-arylation of pyrazoles with allenes at the C-β position of triple bond. Screening in the colorectal cancer cell lines HCT116 and SW620 validated the feasibility of the methodology for generating bioactive compounds. The lead compound 7h which is active against HCT116 and SW620 with IC₅₀ of 1.3 and 1.8 µM, respectively, can be synthesized and purified in a gram process synthetic scale in 7 hours. The mechanical studies indicated that compound 7h can induce cell cycle arrest in the G2/M phase and inhibit proliferation and viability in human colon cancer cells. Overall, compound 7h is represented as a promising starting point for the development of new anti-colorectal cancer drugs.

Microwave-assisted efficient and facile synthesis of tetramic acid derivatives via a one-pot post-Ugi cascade reaction

A facile microwave-assisted method for the synthesis of tetramic acid derivatives has been developed through an Ugi/Dieckmann cyclization strategy with DBU. This two-step one-pot procedure afforded the targeted tetramic acid analogues in good yields. With commercially available Ugi starting materials, microwave irradiation, a simple operation, excellent yields, and a broad scope, this reaction has the potential to produce a large number of tetramic acid analogues, which cannot be easily accessed by the classic synthetic methods.

Doebner-type pyrazolopyridine carboxylic acids in an Ugi four-component reaction

Substituted 1H-pyrazolo[3,4-b]pyridine-4- and 1H-pyrazolo[3,4-b]pyridine-6-carboxamides have been synthetized through a Doebner-Ugi multicomponent reaction sequence in a convergent and versatile manner using diversity generation strategies: combination of two multicomponent reactions and conditions-based divergence strategy. The target products contain as pharmacophores pyrazolopyridine and peptidomimetic moieties with four points of diversity introduced from readily available starting materials including scaffold diversity. A small focused compound library of 23 Ugi products was created and screened for antibacterial activity.

Benzimidazoisoquinoline derivatives inhibit glioblastoma cell proliferation through down-regulating Raf/MEK/ERK and PI3K/AKT pathways

Background

Recent studies showed that benzimidazoleisoquinolinone derivatives exhibit anticancer activity against human cancer cell lines. The aim of this study is to evaluate the anti-tumor effects and mechanisms of benzimidazoleisoquinolinones in isocitrate dehydrogenase-wildtype subtype of human glioblastoma (GBM) cells.

Methods

Human U87 and LN229 cell lines were used to perform the experiments. MTT was applied to screen the effective small molecular inhibitors suppressing growth of GBM cells. Colony formation and BrdU staining assays were performed to assess the inhibition effect of compound-1H on the proliferation of GBM cells. The cell cycle and apoptosis were measured by flow cytometry and western blot to analyze the changes of the relative protein expressions and their signal pathways.

Results

Compound-1H could suppress GBM cells in a time- and dose-dependent manner. Treatment of compound-1H could arrest cell cycle in S phase through up-regulating P21 and P53, and down-regulating cyclin A and E in a dose-dependent manner. Compound-1H also induced mitochondrial-dependent apoptosis by increasing Bax, cleaved caspase-3, cleaved caspase-9 and poly ADP-ribose polymerase expression, and decreasing Bcl-2 expression. Moreover, phosphorylated (p)-AKT and p-ERK levels relating to cell proliferation were dramatically decreased in U87 and LN229 cells.

Conclusions

Our results suggest that it is the first time to report the compound-1H with benzimidazoleisoquinolinone core playing antitumor activity in human glioblastoma cells by inhibiting Raf/MEK/ERK and PI3K/AKT signaling pathways, and it could be as a lead compound for the further development of targeted glioblastoma cancer therapy.

Facile construction of fused benzimidazole-isoquinolinones that induce cell-cycle arrest and apoptosis in colorectal cancer cells

Colorectal cancer (CRC) is one of the most frequent, malignant gastrointestinal tumors, and strategies and effectiveness of current therapy are limited. A series of benzimidazole-isoquinolinone derivatives (BIDs) was synthesized and screened to identify novel scaffolds for CRC. Of the compounds evaluated, 7g exhibited the most promising anti-cancer properties. Employing two CRC cell lines, SW620 and HT29, 7g was found to suppress growth and proliferation of the cell lines at a concentration of ∼20 µM. Treatment followed an increase in G₂/M cell cycle arrest, which was attributed to cyclin B1 and cyclin-dependent kinase 1 (CDK1) signaling deficiencies with simultaneous enhancement in p21 and p53 activity. In addition, mitochondrial-mediated apoptosis was induced in CRC cells. Interestingly, 7g decreased phosphorylated AKT, mTOR and 4E-BP1 levels, while promoting the expression/stability of PTEN. Since PTEN controls input into the PI3K/AKT/mTOR pathway, antiproliferative effects can be attributed to PTEN-mediated tumor suppression. Collectively, these results suggest that BIDs exert antitumor activity in CRC by impairing PI3K/AKT/mTOR signaling. Against a small kinase panel, 7g exhibited low affinity at 5 µM suggesting anticancer properties likely stem through a non-kinase mechanism. Because of the novelty of BIDs, the structure can serve as a lead scaffold to design new CRC therapies.

Functionalized Spiroindolines with Anticancer Activity through a Metal-Free Post-Ugi Diastereoselective One-Pot Cascade Reaction

A post-Ugi diastereoselective one-pot cascade reaction requiring no metal catalyst was developed. The reaction scope was wide with mild conditions and good yields. A collection of spiroindolines was prepared by the protocol and screening tests in several difficult-to-inhibit cancer cell lines were conducted. The relationship of structure and anticancer activities was promising and in the Huh7 cell lines compound 16 j is more potent than Vinbalstine. The cyclization design strategy could be applicable to other multicomponent reactions (MCRs) for synthesizing bioactive and drug-like heterocycles.

Crystal structure of 1-benzyl-3-((4-bromophenyl)amino)-4-(4-methoxyphenyl)-1H-pyrrole-2,5-dione, C24H19BrN2O3

C24H19BrN2O3, monoclinic, P1̅ (no. 2), a = 9.1003(5) Å, b = 9.9785(6) Å, c = 12.9831(6) Å, α = 74.611(5)°, β = 76.063(4)°, γ = 64.264(5)°, V = 1013.17(10) Å3, Z = 2, R gt(F) = 0.0467, wR ref(F 2) = 0.1259, T = 294 K.

Efficient Synthesis of Fused Oxazepino-isoquinoline Scaffolds via an Ugi, Followed by an Intramolecular Cyclization

A mild and efficient protocol was developed for the synthesis of oxazepino-isoquinolines via a one-pot Ugi four-component reaction, followed by the intramolecular addition of the resulting alcohol to an alkyne moiety under microwave irradiation conditions. Notably, this process only required one purification step, providing facile access to two series of complex and potentially interesting biologically active scaffolds.

Diversity oriented synthesis of benzimidazole-based biheterocyclic molecules by combinatorial approach: a critical review

Because of the wide ranging bioactivities associated with the benzimidazole nucleus, this review highlights the advances made in the synthesis of benzimidazole-based biheterocyclic molecules by combinatorial approaches.