120455-03-0Relevant articles and documents
Heterogeneous Photocatalytic Reactions of Azobenzenes on Titanium Dioxide Powder in Methanolic Solution
Shibata, Katsuyoshi,Mimura, Tadashi,Matsui, Masaki,Sugiura, Takashi,Minoura, Hideki
, p. 1318 - 1320 (1988)
Irradiation of a TiO2 powder suspension in a methanolic solution of an azobenzene results in the formation of 1,2,4-triphenyl-1,2,4-triazolidines and a 2-phenylindazole in moderate yields.
Direct Formation of 2-Substituted 2 H-Indazoles by a Pd-Catalyzed Reaction between 2-Halobenzyl Halides and Arylhydrazines
Aljaar, Nayyef,Al-Noaimi, Mousa,Conrad, Jürgen,Beifuss, Uwe
, p. 1408 - 1418 (2021/01/14)
A direct and operationally simple method for the regioselective synthesis of 2-aryl-substituted 2H-indazoles is reported. The Pd-catalyzed reaction between easily available 2-bromobenzyl bromides and arylhydrazines employing Cs2CO3 as the base and t-Bu3PHBF4 as the ligand in DMSO at 120 °C in a sealed tube delivers the 2-substituted-2H-indazoles in a single synthetic step with yields up to 79%. The new method is based on a regioselective intermolecular N-benzylation followed by intramolecular N-arylation and oxidation.
Oxidative cross-dehydrogenative coupling (CDC)viaC(sp2)-H bond functionalization:tert-butyl peroxybenzoate (TBPB)-promoted regioselective direct C-3 acylation/benzoylation of 2H-indazoles with aldehydes/benzyl alcohols/styrenes
Sharma, Richa,Yadav, Lalit,Yadav, Ravi Kant,Chaudhary, Sandeep
, p. 14178 - 14192 (2021/04/22)
An efficient, cost-effective, transition-metal-free, oxidative C(sp2)-H/C(sp2)-H cross-dehydrogenative couplingviaa C(sp2)-H bond functionalization protocol for the regioselective direct C-3 acylation/benzoylation of subst
Metal-free regioselective C-H amination for the synthesis of pyrazole-containing 2H-indazoles
Wang, Kai,Wei, Tingting,Zhang, Yujia,Hou, Jiahao,Bai, Renren,Xie, Yuanyuan
, p. 1787 - 1794 (2021/03/14)
A general and practical regioselective approach for the C-H amination of 2H-indazoles under transition-metal-free conditions was developed. A series of substrates were tested showing eminent functional group tolerance and affording the C-N functionalization products in good to excellent yields. Mechanism studies revealed that a radical process was involved in this transformation.
Synthesis method of 2H-indazole and derivatives thereof
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Paragraph 0027-0040, (2020/12/15)
The invention discloses a synthetic reaction of 2H-indazole and derivatives thereof under a metal-free condition. The new strategy has the advantages of no metal participation, wide substrate range and good functional group compatibility, and an efficient
Efficient synthesis of 2-aryl-2: H -indazoles by base-catalyzed benzyl C-H deprotonation and cyclization
Gao, Wen-Xia,Jin, Guo-Qing,Liu, Miao-Chang,Wu, Hua-Yue,Zhou, Yun-Bing
, p. 14617 - 14620 (2020/12/02)
A straightforward and efficient method for the preparation of 2-aryl-2H-indazoles from ortho-alkyl substituted azoxybenzenes is presented. The reaction proceeds through base-catalyzed benzyl C-H deprotonation and cyclization to afford 2-aryl-2H-indazoles
Regioselective synthesis of 2 H-indazoles using a mild, one-pot condensation-cadogan reductive cyclization
Genung, Nathan E.,Wei, Liuqing,Aspnes, Gary E.
supporting information, p. 3114 - 3117 (2014/06/23)
An operationally simple and efficient one-pot synthesis of 2H-indazoles from commercially available reagents is reported. Ortho-imino-nitrobenzene substrates, generated via condensation, undergo reductive cyclization promoted by tri-n-butylphosophine to afford substituted 2H-indazoles under mild reaction conditions. A variety of electronically diverse ortho-nitrobenzaldehydes and anilines were examined. To further extend the scope of the transformation, aliphatic amines were also employed to form N2-alkyl indazoles selectively under the optimized reaction conditions.
Mesoporous nitrogen doped nano titania - A green photocatalyst for the effective reductive cleavage of azoxybenzenes to amines or 2-phenyl indazoles in methanol
Selvam,Balachandran,Velmurugan,Swaminathan
experimental part, p. 213 - 222 (2012/03/26)
A new nitrogen precursor, hydrazine hydrate was used in the synthesis of nano-sized, N-doped TiO2 photocatalyst by a simple wet impregnation method. This photocatalyst was characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), High resolution transmission electron microscope (HR-TEM), UV-vis diffuses reflectance spectra (DRS), photoluminescence (PL) and X-ray photoelectron spectroscopy (XPS). XRD patterns show that the crystal structure of N-TiO2 resembles anatase phase of TiO2. The UV-vis spectra indicate an increase in absorption of visible light when compared to TiO2. Furthermore XPS analysis reveals the presence of the N atom as O-Ti-N linkage substituting the O atom in the TiO2 lattice and this causes a decrease in oxygen vacancies. N-TiO2 nanoparticles were used as a green and recyclable heterogeneous photocatalyst for rapid and efficient reductive cleavage of azoxybenzene into their corresponding amines or 2-phenylindazoles with methanol at room temperature under N2 atmosphere. Azoxybenzenes in neat methanol afforded anilines, while in aqueous methanol (20% water-80% methanol) they formed corresponding 2-phenyl indazoles. In both reductive cleavages, nano N-TiO2 is more effective than prepared TiO2, showing that the nitrogen doping could be an excellent choice to improve the photoactivity of TiO2.
Synthesis of 2 H-indazoles by the [3 + 2] dipolar cycloaddition of sydnones with arynes
Fang, Yuesi,Wu, Chunrui,Larock, Richard C.,Shi, Feng
, p. 8840 - 8851 (2012/01/02)
A rapid and efficient synthesis of 2H-indazoles has been developed using a [3 + 2] dipolar cycloaddition of sydnones and arynes. A series of 2H-indazoles have been prepared in good to excellent yields using this protocol, and subsequent Pd-catalyzed coupl
Synthesis of 2-aryl-2H-indazoles via copper(I)-catalyzed intramolecular amination reaction
Liu, Rui,Zhu, Yong-ming,Qin, Lie-na,Ji, Shun-jun,Katayama, Haji
, p. 1755 - 1763 (2008/03/14)
A versatile method for the preparation of 2-aryl-2H-indazoles was developed by copper(I)-catalyzed intramolecular amination reaction under the conditions of [CuI/Cs2CO3(250 mol%)/1,4-dioxane/105°C] starting from N'-aryl-N'-(o-bromobe