PEG-mediated catalyst-free expeditious synthesis of 2-substituted benzimidazoles and bis-benzimidazoles under solvent-less conditions

ZnO Nanoparticles Catalyst in the Synthesis of Bioactive Fused Pyrimidines as Anti-breast Cancer Agents Targeting VEGFR-2

BACKGROUND

Pyrimidines emerged as a remarkable class of heterocyclic compounds that have reinforced the pharmaceutical chemistry with various bioactive antitumor agents. Moreover, pyrimidine scaffold displayed VEGFR-2 inhibitory activity. Also, nano-sized catalysts are used in organic reactions in order to speed up the catalytic process.

OBJECTIVE

We were interested herein to synthesize a new series of fused pyrimidines using ZnO(NPs) to investigate their antitumor efficiency against breast MCF7 cancer and their VEGFR- 2 inhibition properties.

METHOD

A simple and efficient method for the synthesis of fused pyrimidines was developed using zinc oxide nanoparticles ZnO(NPs) in refluxing ethanol.

RESULTS

The proposed structures of all new fused pyrimidines are in agreement with their spectral data. Antitumor evaluation of newly fused pyrimidine derivatives against breast MCF-7 cancer was performed. It was apparent that the 2-phenylpyrazolo[1,5-a]pyrimidine derivatives 9a (IC50 = 9.12±1.16 µg/ml), 9c (IC50 = 9.10±1.07 µg/ml) and 9d (IC50 = 9.60±1.22 µg/ml) exhibited equipotent antitumor activity as Tamoxifen (IC50 = 9.11±0.90 µg/ml). Also, the inhibitory activity of the novel fused pyrimidine derivatives on VEGFR-2 as well as Tamoxifen was determined using breast cancer cell line MCF-7. The data was obvious that 2-phenylpyrazolo[1,5-a]pyrimidine derivatives 9a, 9c and 9d exhibited noticeable VEGFR-2 inhibitory effect with % inhibition ranging from 80-84 % versus Tamoxifen 93.5%.

CONCLUSION

We succeeded in this context to synthesize new fused pyrimidines using ZnO(NPs) as anti-breast cancer agents targeting VEGFR-2.

Catalyst-free synthesis of (7E)-7-benzylidene-3,3a,4,5,6,7-hexahydro-2,3-diphenyl-2H-indazole derivatives in PEG-400 as a green and reusable solvent

The reaction of 2,6-bisbenzylidenecyclohexanones and phenylhydrazine in polyethylene glycol (PEG)-400 as a green and reusable solvent under catalyst-free conditions gave hexahydroindazoles as the major product and, in some cases, tetrahydroindazoles were also produced as a minor product. The products were easily separated by simple recrystallisation. The structures of the indazoles were confirmed using FTIR and NMR spectroscopy. Two X-ray structures are reported.

Experimental and theoretical approving of anomeric based oxidation in the preparation of 2-sbstituted benz-(imida, oxa and othia)-zoles using [2,6-DMPy-NO2]C(NO2)3 as a novel nano molten salt catalyst

The synthesis of [2,6-DMPy-NO₂]C(NO₂)₃ as a novel NMS and its application in the synthesis of 2-sbstituted benz-(imida, oxa and othia)-zoles via a new mechanistic approach was supported by theoretical studies.

Nickel–glycerol: an efficient, recyclable catalysis system for Suzuki cross coupling reactions using aryl diazonium salts

A palladium free, chemoselective and environmentally benign protocol for a C–C bond formation reaction.

Fragment-assisted hit investigation involving integrated HTS and fragment screening: Application to the identification of phosphodiesterase 10A (PDE10A) inhibitors

Fragment-based drug design (FBDD) relies on direct elaboration of fragment hits and typically requires high resolution structural information to guide optimization. In fragment-assisted drug discovery (FADD), fragments provide information to guide selection and design but do not serve as starting points for elaboration. We describe FADD and high-throughput screening (HTS) campaign strategies conducted in parallel against PDE10A where fragment hit co-crystallography was not available. The fragment screen led to prioritized fragment hits (IC50's ∼500μM), which were used to generate a hypothetical core scaffold. Application of this scaffold as a filter to HTS output afforded a 4μM hit, which, after preparation of a small number of analogs, was elaborated into a 16nM lead. This approach highlights the strength of FADD, as fragment methods were applied despite the absence of co-crystallographical information to efficiently identify a lead compound for further optimization.

Grindstone chemistry: protic ionic liquid-substrate tuned green synthesis of 1,2-disubstituted and 2-substituted benzimidazoles with outstanding selectivity

An environmentally benign and highly substrate-protic ionic liquid controlled synthesis of 1,2-disubstituted and 2-substituted benzimidazoles with outstanding selectivity is demonstrated through grinding a mixture of OPD, aldehydes and catalyst.

Hg2+-induced deprotonation of an anthracene-based chemosensor: set–reset flip-flop at the molecular level using Hg2+ and I− ions

A simple chemosensor 1 shows a “turn-off” sensing of Hg²⁺ ions, whereas the in situ formed Hg²⁺ complex can be used for “turn-on” sensing with I⁻ ions. These fluorescence changes have been used for the construction of a set–reset flip-flop circuit.

A highly efficient oxidative condensation reaction for selective protein conjugation

A novel oxidative conjugation reaction between aryl diamine and aldehyde was used to site-specifically label a protein.

Metal catalyst free one-pot synthesis of 2-arylbenzimidazoles from α-aroylketene dithioacetals

An efficient green synthetic approach has been developed towards the synthesis of 2-aryl substituted benzimidazoles 4 from α-aroylketene dithioacetals (AKDTAs) 1 and phenylenediamine (OPD) 2.

NaHSO4-SiO2-Promoted Solvent-Free Synthesis of Benzoxazoles, Benzimidazoles, and Benzothiazole Derivatives

An efficient protocol has been developed for the preparation of a library of benzoxazole, benzimidazole, and benzothiazole derivatives from reactions of acyl chlorides witho-substituted aminoaromatics in the presence of catalytic amount of silica-supported sodium hydrogen sulphate under solvent-free conditions. Simple workup procedure, high yield, easy availability, reusability, and use of ecofriendly catalyst are some of the striking features of the present protocol.

Al(OTf)3 Catalysed Friedel-Crafts Michael Type Addition of Indoles to α,β-Unsaturated Ketones with PEG-200 as Recyclable Solvent

An Al(OTf)3 catalysed efficient Friedel–Crafts Michael type addition of indoles to α,β-unsaturated ketones using recyclable PEG-200 as an alternative reaction solvent is disclosed. The reaction under microwave irradiation is clean, leads to excellent yields in minutes and reduces the use of volatile organic compounds.