I<sub>2</sub>-Mediated Oxidative C–N Bond Formation for Metal-Free One-Pot Synthesis of Di-, Tri-, and Tetrasubstituted Pyrazoles from α,β-Unsaturated Aldehydes/Ketones and Hydrazines
An I2-mediated metal-free oxidative C–N bond formation methodology has been established for the regioselective pyrazole synthesis. This practical and eco-friendly one-pot protocol requires no isolation of the less stable intermediates hydrazones and provides a facile access to a variety of di-, tri-, and tetrasubstituted (aryl, alkyl, and/or vinyl) pyrazoles from readily available α,β-unsaturated aldehydes/ketones
I 2介导的无金属氧化C–N键形成方法已建立用于区域选择性吡唑合成。这种实用且环保的一锅操作方案无需分离不稳定程度较高的中间体s,并易于从容易获得的多种二,三和四取代(芳基,烷基和/或乙烯基)吡唑中分离α,β-不饱和醛/酮和肼盐。
PYRAZOLE DERIVATIVES
申请人:Hua Medicine (Shanghai) Ltd.
公开号:EP3400220B1
公开(公告)日:2021-03-24
Functionalized 4-Aminoquinolines by Rearrangement of Pyrazole N-Heterocyclic Carbenes
作者:Andreas Schmidt、Niels Münster、Andrij Dreger
DOI:10.1002/anie.200905436
日期:2010.4.1
Thermal decarboxylation of 1‐phenylpyrazolium‐3‐carboxylates from the mesomeric betaine class of substances leads to pyrazole‐N‐heterocyclic carbenes, which immediately rearrange to multiply substituted 4‐aminoquinolines (see scheme). These species are of interest for the synthesis of heterocycles and pharmacologically active compounds.