Copper-Promoted Oxidative Intramolecular C-H Amination of Hydrazones to Synthesize 1<i>H</i>
-Indazoles and 1<i>H</i>
-Pyrazoles Using a Cleavable Directing Group
A facile and efficient copper‐promoted oxidative intramolecular C–H amination of hydrazones for the synthesis of 1H‐indazoles and 1H‐pyrazoles was developed using a tracelessly cleavable directing group. This reaction is characterized by its mild conditions, operational simplicity, readily available reagents, and excellent yields. A tentative mechanism for Cu‐mediated C–H‐oxidative amination was proposed
Arylation Using Sulfonamides: Phenylacetamide Synthesis through Tandem Acylation–Smiles Rearrangement
作者:Helen L. Barlow、Pauline T. G. Rabet、Alastair Durie、Tim Evans、Michael F. Greaney
DOI:10.1021/acs.orglett.9b03429
日期:2019.11.15
and heterocyclic sulfonamides react with phenylacetyl chlorides to produce benzhydryl derivatives in a single step. The reaction proceeds via tandem amide bond formation/Dohmori-Smiles rearrangement under the simple conditions of an aqueous base. In the case of o-nosylamides, a further reaction takes place at the nitro group to yield indazoles.
A NOVEL AND EFFICIENT SYNTHESIS OF 3-ARYL AND 3-HETEROARYL SUBSTITUTED-1<i>H</i>-INDAZOLES AND THEIR MANNICH DERIVATIVES
作者:Süleyman Servi、Z. Rüstem Akgün
DOI:10.1081/scc-120014767
日期:2002.1
ABSTRACT A general and highly convenientprocedure for the synthesis of 3-heteroaryl and 3-aryl substituted-1H-indazoles has been developed. These compounds (3a–f) were synthesized in good yield by refluxing the NaHSO3 adduct of heteroaromatic and aromatic aldehyde and phenyl hydrazine in DMF. This procedure is more general and shorter than earlier methods. Five new 3-hetero-aryl substituted-1H-indazoles
Synthesis of dihydroindazolo[2,3-<i>f</i>]phenanthridin-5(6<i>H</i>)-ones <i>via</i> Rh(<scp>iii</scp>)-catalyzed C–H activation of 2-aryl indazoles and annulation with iodonium ylides
An efficient syntheticroute to indazole-fused dihydrophenanthridinones in excellent to almost quantitative yields under mild reaction conditions was developed. The reaction utilizes the acid-controlled Rh(III)-catalyzed C–H activation of 3-arylindazoles followed by their annulation with readily available hypervalent iodonium ylides. This methodology afforded a wide range of products that could be
开发了一种在温和反应条件下以优异至几乎定量的产率合成吲唑稠合二氢菲啶酮的有效合成路线。该反应利用酸控制的 Rh( III ) 催化的 3-芳基吲唑的 C-H 活化,然后用现成的高价碘鎓叶立德进行环化。这种方法提供了广泛的产品,只需简单的过滤即可分离,无需柱层析。此外,催化体系可以循环使用至少八次,收率很高,这可能使其适合工业生产。此外,合成的二氢吲唑并[2,3 - f ]phenanthridin-5(6 H)-表示它们可能具有作为新型荧光材料的潜在应用。
Synthesis of 3-Substituted Indazoles from Arynes and <i>N</i>-Tosylhydrazones
作者:Pan Li、Jingjing Zhao、Chunrui Wu、Richard C. Larock、Feng Shi
DOI:10.1021/ol201086g
日期:2011.7.1
Readily available, stable, and inexpensive N-tosylhydrazones react with arynes under mild reaction conditions to afford 3-substituted indazoles in moderate to good yields. The reaction appears to involve a dipolar cycloaddition of in situ generated diazo compounds and arynes.