A Versatile New Synthetic Route to 1<i>N</i>-Hydroxyindazoles

Lehmann, Fredrik; Koolmeister, Tobias; Odell, Luke R.; Scobie, Martin

doi:10.1021/ol902085k

Cited by 15 publications

(12 citation statements)

References 27 publications

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“…The tautomers and the equilibrium between the structures often arise important characteristic or behavioral changes in the aromaticity, acidity-basicity, chemical, and even biological properties (Catalán et al, 1996). Several comprehensive structure analysis studies using UV spectroscopy, molecular refractivity measurement, x-ray diffraction, Raman spectroscopy, 1 H and 13 C NMR studies confirm the structure of 1H-Indazole which predominatesin the gaseous phase (Lehmann et al, 2009). 1H-Indazole possesses diastereogenic center on N−1 position as the hydrogen atom of NH bond stays out of the plane concerning the rest of the atoms (Elguero et al, 2013).…”

Section: Tautomerism In Indazole and Their Relative Stabilitiesmentioning

confidence: 99%

A review on synthetic strategy, molecular pharmacology of indazole derivatives, and their future perspective

Mal

Malik

Mahapatra

et al. 2022

Drug Development Research

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With different nitrogen-containing heterocyclic moieties, Indazoles earn one of the places among the top investigated molecules in medicinal research. Indazole, an important fused aromatic heterocyclic system containing benzene and pyrazole ring with a chemical formula of C 7 H 6 N 2 , is also called benzopyrazole. Indazoles consist of three tautomeric forms in which 1H-tautomers (indazoles) and 2H-tautomers (isoindazoles) exist in all phases. The tautomerism in indazoles greatly influences synthesis, reactivity, physical and even the biological properties of indazoles.The thermodynamic internal energy calculation of these tautomers points view 1H-indazole as the predominant and stable form over 2H-indazole. The natural source of indazole is limited and exists in alkaloidal nature (i.e., nigellidine, nigeglanine, nigellicine, etc.) found from Nigella plants. Some of the FDA-approved drugs like Axitinib, Entrectinib, Niraparib, Benzydamine, and Granisetron are being used to treat renal cell cancer, non-small cell lung cancer (NSCLC), epithelial ovarian cancer, chronic inflammation, chemotherapy-induced nausea, vomiting, and many more uses. Besides all these advantages regarding its biological activity, the main issue about indazoles is the less abundance in plant sources, and their synthetic derivatives also often face problems with low yield. In this review article, we discuss its chemistry, tautomerism along with their effects, different schematics for the synthesis of indazole derivatives, and their different biological activities.

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Section: Tautomerism In Indazole and Their Relative Stabilitiesmentioning

confidence: 99%

A review on synthetic strategy, molecular pharmacology of indazole derivatives, and their future perspective

Mal

Malik

Mahapatra

et al. 2022

Drug Development Research

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“…Nitroso alkenesa re typically generatedi nsitu because of their instability and high reactivity.H owever,t he nitro group can be employeda sagood nitroso precursor for the generation of reactiven itroso surrogates in hetero-dienophileD iels-Alder reactions. [33] Recently,S cobie and co-workers [34] reported an interesting new synthetic route to 1N-hydroxyindazoles (54), in which 2-nitrobenzylamines (53)w ere used as the nitroso precursor in the presence of methanolic sodium hydroxide (Scheme 20).…”

Section: Scheme14 Annulation Of Enalswith Nitrosoarenes Catalyzed Bymentioning

confidence: 99%

Recent Advances in Highly Selective Applications of Nitroso Compounds

et al. 2016

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Abstract:Over the past few years, substantial progress has been achieved in the development of nitroso-related organic chemistry. Annulations of nitroso compounds with other π-conjugated systems, especially the notable hetero Diels-Aldertype reaction, have drawn much interest from organic chemists, because of their regioselective, enantioselective and highly efficient advantages. In addition, the N-nitroso moiety can also be employed as powerful and transformable directing group in specific C-H direct functionalization reactions. Herein, we summarized the versatile applications of nitroso compounds as useful building blocks in the selective synthesis of diverse molecules in recent years.

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“…In this case, when allene 1k was treated with N -hydroxybenzotriazole 2a , we obtained 3qa in lower yield (17%); the majority of unreacted allene 1k was recovered, indicating that an allene is less reactive than the corresponding alkyne under these conditions. Interestingly, 1-hydroxyindazole ( 2e ), N -hydroxy-4-quinolone ( 2f ), and N -hydroxyquinazolinediones ( 2g ) did not react with alkynes under the same conditions (Table , entries 18–20). The reasons for this are not clear to us at this point.…”

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confidence: 97%

Gold-Catalyzed Addition of N-Hydroxy Heterocycles to Alkynes and Subsequent 3,3-Sigmatropic Rearrangement

et al. 2013

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Gold-catalyzed intermolecular addition of hydroxybenzotriazole derivatives to alkynes at room temperature, gives vinyl ethers 3 in high yields and with excellent regioselectivity. Unlike many other vinyl ethers, 3 can easily be purified by regular silica-gel chromatography. On heating, 3,3-sigmatropic rearrangement of 3 gives access to highly functionalized benzotriazoles. This two-step sequence represents an efficient oxygen transfer protocol which incorporates a nucleophilic oxygen atom into an alkyne group. Reaction of 3 with an electrophilic fluorinating reagent (Selectfluor) gives a fluorinated ketone regioselectively and in high yield.

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A Versatile New Synthetic Route to 1N-Hydroxyindazoles

Cited by 15 publications

References 27 publications

A review on synthetic strategy, molecular pharmacology of indazole derivatives, and their future perspective

A review on synthetic strategy, molecular pharmacology of indazole derivatives, and their future perspective

Recent Advances in Highly Selective Applications of Nitroso Compounds

Gold-Catalyzed Addition of N-Hydroxy Heterocycles to Alkynes and Subsequent 3,3-Sigmatropic Rearrangement

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