Pyrazole derivatives bearing a cyclopropyl group at C3-position and an amino substituent at C5 were successfully employed in palladium-catalyzed direct arylations. These couplings were performed using air-stable PdCl(C₃H₅)(dppb) catalyst associated to KOAc as inexpensive base, and afforded regioselectively the C4-arylated pyrazoles without decomposition of the cyclopropyl unit and formation of amination products. A wide variety of functional groups on the aryl bromide including electron-withdrawing and electron-donating ones such as nitrile, nitro, propionyl, ester, trifluoromethyl, chloro, fluoro or methoxy was tolerated. Moreover, from 5-aminopyrazoles bearing N-2′-bromoaryl or 2′-bromobenzenesulfonamide substituent on the amino group, intramolecular Pd-catalyzed direct arylations allowed the formation of tricyclic compounds by formation of 5- or 6-membered rings. © 2018 Elsevier Science. All rights reserved.

在钯催化的直接芳基化中成功使用了在C3位带有环丙基和在C5带有氨基取代基的吡唑衍生物。这些偶联使用与KOAc缔合的空气稳定的PdCl（C ₃ H ₅）（dppb）催化剂作为廉价碱进行，并选择性地提供了C4-芳基吡唑，而没有环丙基单元的分解和胺化产物的形成。芳基溴化物上的多种官能团，包括吸电子和供电子基，例如腈，硝基，丙酰基，酯，三氟甲基，氯，氟或甲氧基，是可以耐受的。此外，由带有N的5-氨基吡唑氨基上的-2'-溴芳基或2'-溴苯磺酰胺取代基，分子内Pd催化的直接芳基化通过形成5元或6元环而形成三环化合物。©2018爱思唯尔科学。版权所有。