Abstract An efficient and novel protocol for pyrazole synthesis has been developed by using fluoroboric acid as the acid catalyst. Simple and easily available 1,3-diketone and hydrazine derivatives are taken as the substrates for this purpose. The reaction entails mild reaction conditions and produces desired pyrazoles in good to excellent yields. Easy accessibility, easy handling, broad substrate
Copper-catalyzed C–N cross-coupling of arylboronic acids with N-acylpyrazoles
作者:Jin Zhang、Run-Ping Jia、Dong-Hui Wang
DOI:10.1016/j.tetlet.2016.06.044
日期:2016.8
A copper-catalyzed C–N bond forming reaction of arylboronicacids and N-acylpyrazoles was developed. This procedure used N-acetyl protected pyrazoles as starting material instead of free pyrazoles (NH). The reaction worked under neutral conditions and did not require any base or ligand. The reaction showed good functional group tolerance.
Herein an efficient and simple protocol was developed for the synthesis of pyrazoles and phthalazin-1(2H)-ones from a common precursor hydrazines catalyzed by nickelchloride. The reactions proceeded in water at room temperature. The advantages of the protocol are that both the medicinally important scaffolds could be synthesized with low-cost catalyst, green solvent, relatively lower reaction time
Cross‐Coupling between Hydrazine and Aryl Halides with Hydroxide Base at Low Loadings of Palladium by Rate‐Determining Deprotonation of Bound Hydrazine
作者:Justin Y. Wang、Kyoungmin Choi、Stephan J. Zuend、Kailaskumar Borate、Harish Shinde、Roland Goetz、John F. Hartwig
DOI:10.1002/anie.202011161
日期:2021.1.4
to give the product. The selectivity of the hydroxide complex with hydrazine to form aryl over diaryl hydrazine was lower than that of the chloride complex, as well as the catalyticreaction. In contrast, the selectivity of the chloride complex closely matched that of the catalyticreaction, indicating that the aryl hydrazine is derived from this complex. Kinetic studies showed that the coupling process
这里报道了钯催化的肼与(杂)芳基氯化物和溴化物的 C-N 偶联,形成芳基肼,催化剂负载量低至 100 ppm 的 Pd 和 KOH 作为碱。机理研究揭示了两种催化剂静止状态:芳基钯 (II) 氢氧化物和芳基钯 (II) 氯化物。这些化合物存在于两个相互关联的催化循环中,并与肼和碱或肼单独反应生成产物。与二芳基肼相比,氢氧化物与肼形成芳基的选择性低于氯化物络合物,催化反应也是如此。相比之下,氯化物络合物的选择性与催化反应的选择性非常接近,表明芳基肼是从该络合物中衍生出来的。