CuO nanoparticle catalysed synthesis of 2H-indazoles under ligand free conditions

Khatun, Nilufa; Gogoi, Anupal; Basu, Pallabita; Das, Prasenjit; Patel, Bhisma K.

doi:10.1039/c3ra45298k

Cited by 36 publications

(25 citation statements)

References 32 publications

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“…The 2H -indazoles 5 – 8 were synthesised using a two-step approach including a Schiff base formation followed by intramolecular cyclisation 13 , 14 using microwave irradiation to reduce the reaction time of each step from 12 h to a few minutes. The condensation of aniline with 2-bromobenzaldehyde in presence of MgSO 4 under microwave activation allowed access to imine 1 – 4 in excellent yields.…”

Section: Resultsmentioning

confidence: 99%

Design of selective COX-2 inhibitors in the (aza)indazole series. Chemistry, in vitro studies, radiochemistry and evaluations in rats of a [¹⁸F] PET tracer

Elie

Vercouillie

Arlicot

et al. 2018

Journal of Enzyme Inhibition and Medicinal Chemistry

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A series of novel derivatives exhibiting high affinity and selectivity towards the COX-2 enzyme in the (aza) indazole series was developed. A short synthetic route involving a bromination/arylation sequence under microwave irradiation and direct C–H activation were established in the indazole and azaindazole series respectively. In vitro assays were conducted and structural modifications were carried out on these scaffolds to furnish compound 16 which exhibited effective COX-2 inhibitory activity, with IC50 values of 0.409 µM and an excellent selectivity versus COX-1. Radiolabeling of this most potent derivative [18F]16 was achieved after boron ester release and the tracer was evaluated in vivo in a rat model of neuroinflammation. All chemistry, radiochemistry and biological experimental data are discussed.

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Section: Resultsmentioning

confidence: 99%

Design of selective COX-2 inhibitors in the (aza)indazole series. Chemistry, in vitro studies, radiochemistry and evaluations in rats of a [¹⁸F] PET tracer

Elie

Vercouillie

Arlicot

et al. 2018

Journal of Enzyme Inhibition and Medicinal Chemistry

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“…White solid; yield: 1.80 g (93%); mp 81-82°C (Lit. 16 2-(4-methoxyphenyl)-2H-indazole (4b) [16]. Brown solid; yield: 2.04 g (91%); mp 132-133°C (Lit.…”

Section: Recovery Of the Catalystmentioning

confidence: 99%

“…Thus, the development of efficient and applicable methods for selective synthesis of 2 H ‐indazoles is of great significance to synthetic chemists. To overcome the problem of selectivity, several promising approaches have been developed in recent years . Although, a plenty of these procedure are useful and efficient; however, they are usually accompanied by one or more drawbacks such as long reaction times, the formation of regioisomers, requirement for expensive ligands, and limited substrate scope.…”

Section: Introductionmentioning

confidence: 99%

Highly Efficient One‐Pot Three Component Synthesis of 2H‐Indazoles by Consecutive Condensation, C–N and N–N Bond Formations Using Cu/Aminoclay/Reduced Graphene Oxide Nanohybrid

Behrouz

2016

Journal of Heterocyclic Chem

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A simple and straightforward one‐pot three‐component synthesis of 2H‐indazoles through copper‐catalyzed consecutive condensation, C–N and N–N bond formations of easily accessible starting materials under ligand‐free conditions is described. In this protocol, treatment of substituted 2‐bromobenzaldehydes, structurally diverse amines, and [bmim]N3 in the presence of Cu/aminoclay/reduced graphene oxide nanohybrid (Cu/AC/r‐GO nanohybrid) as an efficient heterogeneous catalyst affords the corresponding 2H‐indazoles in good to excellent yields. The influence of effective parameters on the efficient progress of the reaction was studied. The Cu/AC/r‐GO nanohybrid is a stable and inexpensive catalyst that could be simply prepared, recovered, and reused for several reaction runs with no significant decrease in its reactivity.

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“…[1,[42][43][44][45][46][47][48][49][50][51][52][53][54] A common way for the formation of highly regioselective 2H-indazoles is based on the intramolecular coupling of properly pre-functionalized substrates including 2halobenzaldehydes. [55][56][57][58][59][60] This eco-efficient one-pot approach includes consecutive CÀ N and NÀ N bonds formation with extrusion of N 2 to corresponding 2H-indazoles.…”

Section: Introductionmentioning

confidence: 99%

Copper(I) Complex of Dihydro Bis(2‐Mercapto Benzimidazolyl) Borate as an Efficient Homogeneous Catalyst for the Synthesis of 2H‐Indazoles and 5‐Substituted 1H‐Tetrazoles

et al. 2021

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In this work, catalytic activity of a series of copper(I) complexes containing dihydrobis(2-mercapto-benzimidazolyl) borate (Bb), and phosphine co-ligands was investigated in the synthesis of N-heterocycle compounds including 2H-indazoles and 5-substituted 1H-tetrazoles. The copper(I) complex containing tricyclohexylphosphine co-ligand, [Cu(Bb)(PCy 3)], displayed the highest catalytic activities for the formation of 2H-indazoles and 1H-tetrazoles. Apart from the nontoxicity and strong σ-donating ability of the introduced ligands, the introduced catalyst required easy handling processes. The catalytic reactions were successfully performed at low catalyst loadings in either PEG-200 or DMF and in relatively short reaction times. The diversity of these reactions was also explored with 20 and 12 examples. Finally, the current catalytic system is amenable to large-scale production of these N-heterocycle compounds.

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CuO nanoparticle catalysed synthesis of 2H-indazoles under ligand free conditions

Cited by 36 publications

References 32 publications

Design of selective COX-2 inhibitors in the (aza)indazole series. Chemistry, in vitro studies, radiochemistry and evaluations in rats of a [¹⁸F] PET tracer

Design of selective COX-2 inhibitors in the (aza)indazole series. Chemistry, in vitro studies, radiochemistry and evaluations in rats of a [¹⁸F] PET tracer

Highly Efficient One‐Pot Three Component Synthesis of 2H‐Indazoles by Consecutive Condensation, C–N and N–N Bond Formations Using Cu/Aminoclay/Reduced Graphene Oxide Nanohybrid

Copper(I) Complex of Dihydro Bis(2‐Mercapto Benzimidazolyl) Borate as an Efficient Homogeneous Catalyst for the Synthesis of 2H‐Indazoles and 5‐Substituted 1H‐Tetrazoles

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CuO nanoparticle catalysed synthesis of 2H-indazoles under ligand free conditions

Cited by 36 publications

References 32 publications

Design of selective COX-2 inhibitors in the (aza)indazole series. Chemistry, in vitro studies, radiochemistry and evaluations in rats of a [18F] PET tracer

Design of selective COX-2 inhibitors in the (aza)indazole series. Chemistry, in vitro studies, radiochemistry and evaluations in rats of a [18F] PET tracer

Highly Efficient One‐Pot Three Component Synthesis of 2H‐Indazoles by Consecutive Condensation, C–N and N–N Bond Formations Using Cu/Aminoclay/Reduced Graphene Oxide Nanohybrid

Copper(I) Complex of Dihydro Bis(2‐Mercapto Benzimidazolyl) Borate as an Efficient Homogeneous Catalyst for the Synthesis of 2H‐Indazoles and 5‐Substituted 1H‐Tetrazoles

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Design of selective COX-2 inhibitors in the (aza)indazole series. Chemistry, in vitro studies, radiochemistry and evaluations in rats of a [¹⁸F] PET tracer

Design of selective COX-2 inhibitors in the (aza)indazole series. Chemistry, in vitro studies, radiochemistry and evaluations in rats of a [¹⁸F] PET tracer