1006-19-5Relevant academic research and scientific papers
Reactions of Hydrazides and Hydrazones with n-Butyl-lithium
Barton, Derek H. R.,Lukacs, Gabor,Wagle, Dilip
, p. 450 - 452 (1982)
Aromatic hydrazides give indazol-3(2H)-ones in good yield when treated with 3 equivalents of n-butyl-lithium; aliphatic and heterocyclic hydrazides afford the corresponding aldehydes under the same conditions.
Synthesis of Indazolones via Friedel-Crafts Cyclization of Blocked (Masked) N-Isocyanates
Elkaeed, Eslam B.,An, Jing,Beauchemin, André M.
, p. 9890 - 9897 (2017/09/23)
Nitrogen-substituted isocyanates (N-isocyanates) are rare amphoteric reagents with high, but underdeveloped synthetic potential. Herein, we study the formation of indazolones by Friedel-Crafts cyclization of N-isocyanates using blocked (masked) N-isocyanate precursors: the effect of the masking group and the reaction scope have been delineated. Substrate synthesis has also been improved using a reported copper-catalyzed coupling of arylbismuth(V) reagents that is compatible with the hemilabile OPh blocking group.
Rhodium(III)-catalyzed N-nitroso-directed C-H addition to ethyl 2-oxoacetate for cycloaddition/fragmentation synthesis of indazoles
Chen, Jinsen,Chen, Pei,Song, Chao,Zhu, Jin
, p. 14245 - 14249 (2015/02/05)
RhIII-catalyzed N-nitroso-directed C-H addition to ethyl 2-oxoacetate allows subsequent construction of indazoles, a privileged heterocycle scaffold in synthetic chemistry, through the exploitation of reactivity between the directing group and installed group. The formal [2+2] cycloaddition/fragmentation reaction pathway identified herein, a unique reactivity pattern hitherto elusive for the N-nitroso group, emphasizes the importance of forward reactivity analysis in the development of useful C-H functionalization-based synthetic tools. The synthetic utility of the protocol is demonstrated with the synthesis of a tri-cyclic-fused ring system. The diversity of covalent linkages available for the nitroso group should enable the extension of the genre of reactivity reported herein to the synthesis of other types of heterocycles.
A general, one-step synthesis of substituted indazoles using a flow reactor
Wheeler, Rob C.,Baxter, Emma,Campbell, Ian B.,MacDonald, Simon J. F.
experimental part, p. 565 - 569 (2011/12/02)
Flow chemistry is a rapidly emerging technology within the pharmaceutical industry, both within medicinal and development chemistry groups. The advantages of flow chemistry, increased safety, improved reproducibility, enhanced scalability, are readily apparent, and we aimed to exploit this technology in order to provide small amounts of pharmaceutically interesting fragments via a safe and scalable route, which would enable the rapid synthesis of multigram quantities on demand. Here we report a general and versatile route which utilises flow chemistry to deliver a range of known and novel indazoles, including 3-amino and 3-hydroxy analogues.
Regioselective synthesis of 1-alkyl- Or 1-aryl-1H-indazoles via copper-catalyzed cyclizations of 2-haloarylcarbonylic compounds
Vina, Dolores,Del Olmo, Esther,Lopez-Perez, Jose L.,Feliciano, Arturo San
, p. 525 - 528 (2007/10/03)
A general method for the one-step regioselective synthesis of 1-alkyl- or 1-aryl-1H-indazoles from ortho-halogenated alkanoylphenones, benzophenones, and arylcarboxylic acids, via copper-catalyzed amination, was developed by using 0.2% mol of CuO in the p
The Heterocyclization of N',N'-Disubstituted 2-Halogenobenzohydrazides to 1,1-Disubstituted Indazol-3-ylio Oxides
Aran, Vicente J.,Asensio, Juan L.,Ruiz, Jose R.,Stud, Manfred
, p. 1322 - 1345 (2007/10/02)
The intramolecular cyclization of N',N'-disubstituted 2-halogenobenzohydrazides is a good method for the synthesis of the previously unknown indazol-3-ylio oxides.The Z/E rotamerism found in the starting hydrazides, the effects of the nature and the activ
Reactivity of 1,1-Disubstituted Indazol-3-ylio Oxides: Synthesis of some Substituted Indazolols and Indazolinones
Aran, Vicente J.,Asensio, Juan L.,Ruiz, Jose R.,Stud, Manfred
, p. 1119 - 1128 (2007/10/02)
Some aspects of the reactivity of 1,1-disubstituted indazol-3-ylio oxides (indazolol-derived aminimides) have been studied.Treatment of these compounds with hydrochloric acid gave the corresponding indazolium salts which, through elimination of an alkyl c
Preparation of Imidazoquinazolin-5(3H)-ones and Related Tricyclic Systems Using a Novel, Double Displacement Reaction
Peet, Norton P.,Malecha, James,LeTourneau, Michael E.,Sunder, Shyam
, p. 257 - 264 (2007/10/02)
New methodology is described for the construction of tricyclic heterocycles.Thus, a double displacement reaction of 1-(2-fluorobenzoyl)-2-methylthio-2-imidazoline (8a) with 1,1-dialkylhydrazines gave 10-substituted 2,10-dihydroimidazoquinazolin-5(3H)-ones in good yield.The corresponding 1-(2-nitrobenzoyl)-2-methylthio-2-imidazolines also underwent double displacement reactiones with hydrazines.Other tricyclics made using double displacement reactions were pyrimidoquinazolines, imidazopyridopyrimidines, and imidazopyrazolopyrimidines.Treatment of 8a with hydrazine hydrate or methylhydrazine gave products resulting from displacement, but did not afford fused benzotriazepinones.
Acyl Derivatives of Indazolin-3-one
Anderson, Robert M.
, p. 3933 - 3959 (2007/10/02)
1- and 2-Ethanoyl-, propanoyl-, butanoyl- and benzoylindazolin-3-ones have been prepared and the 2-isomers have been shown to exist in two tautomeric forms.Sulphonylation and further acylation of these compounds are described and some rearrangements in the series are discussed.
ACTION OF NITROUS ACID ON N-SUBSTITUTED-ISATINIC ACIDS. DISPROPORTIONATION TO INDAZOLOLS.
Baiocchi,Leandro,Picconi, Giuseppe
, p. 3651 - 3652 (2007/10/02)
By reacting N-substituted-2-isatinic acids with nitrous acid, indazolols, N-nitroso-N-substituted anthranilic acids and the esters of said acids with the above mentioned indazolols were obtained through disproportionation of the N-nitroso-N-substituted-isatinic acids.
