Synthesis Of Indazoles Research Articles

Reactions of hydroxybenzophenone with hydrazines

AbstractThe reaction of 2,2′,4,4′‐tetrahydroxybenzophenone with hydrazines under different conditions gave the corresponding indazol‐1,3‐benzenediol derivatives. It is an interesting and unique approach to the synthesis of indazoles. However, the reactions of 2‐hydroxybenzophenone and 2,2′‐dihydroxybenzophenone under the same conditions yielded only the hydrazones.

Synthesis of pyrazoles and indazoles from aliphatic diazo compounds (review)

The literature data on the synthesis of indazoles and pyrazoles from aliphatic diazo compounds and compounds containing a carbon-carbon triple bond are reviewed. The dependence of the direction of the reaction and the yields of the final products on the structures of the reagents is discussed. The rearrangements that accompany cycloaddition are examined. Modern views of the mechanisms of the reactions discussed in the review are presented.

Intramolecular cyclization of nitrile imines. Synthesis of indazoles, fluorenes, and aza analogs

Intramolecular cyclization of nitrile imines. Synthesis of indazoles, fluorenes, and aza analogs

1,2,3-Benzotriazines

Although many 3,4-dihydro-4-oxo and -imido-derivatives of 1,2,3-benzotriazine are known, 1,2,3-benzotriazine itself was previously unknown, only very few of its aromatic derivatives had been reported, and no general methods for their synthesis had been described.1,2,3-Benzotriazine, some simple 4-alkyl and aryl derivatives, and a pyrido[1,2,3]triazine are now described, together with four general syntheses of the ring system. These involve (i) oxidation of the hydrazones of o-azidophenyl ketones and thermal cyclisation of the resulting o-azidophenyldiazoalkanes, (ii) oxidative cyclisation of the hydrazones of o-aminophenyl ketones, (iii) oxidation of 1- and 2-aminoindazoles, and (iv) oxidation of N-aminoquinazolin-2-ones. Methods (iii) and (iv) involve heterocyclic ring expansions, the latter with loss of carbon monoxide.1,2,3-Benzotriazines are susceptible to nucleophilic addition to the 3,4-bond, and the high reactivity of benzotriazine in this reaction explains the failure of earlier attempts to synthesise it.Preparation of the azido-hydrazones required for method (i) from azido-ketones in the standard way led to an unusual but useful synthesis of indazoles.

Synthesis of indazoles using polyphosphoric acid—I

Indazoles have been synthesized from nitrophenyl-hydrazones of several acetophenones, benzaldehydes and benzophenones, employing polyphosphoric acid as catalyst.

Synthesis of indazoles from acetophenone p-nitro-phenylhydrazones using polyphosphoric acid as a condensing agent

Synthesis of indazoles from acetophenone p-nitro-phenylhydrazones using polyphosphoric acid as a condensing agent

Indazole Analog of Tryptamine: A New Synthesis of Indazoles

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTIndazole Analog of Tryptamine: A New Synthesis of IndazolesC. AinsworthCite this: J. Am. Chem. Soc. 1957, 79, 19, 5242–5245Publication Date (Print):October 1, 1957Publication History Published online1 May 2002Published inissue 1 October 1957https://doi.org/10.1021/ja01576a047RIGHTS & PERMISSIONSArticle Views443Altmetric-Citations24LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (524 KB) Get e-Alerts Get e-Alerts