Discovery of ectoparasiticidal hydrazonotrifluoromethanesulfonanilides
摘要:
A series of hydrazonotrifluorosulfonanilide derivatives were synthesized and evaluated for in vitro activity against the ectoparasites Ctenocephalides felis and Rhipicephalus sanguineus. Some compounds with excellent activity against tick were identified. (C) 2009 Elsevier Ltd. All rights reserved.
Abnormal Fischer indolization and its related compounds. XXII. Fischer indolization of ethyl pyruvate 2-(2-chloro- and 2,6-dichlorophenyl)methylhydrazones.
The Fischer indolization of ethyl pyruvate 2-(2-chlorophenyl)methylhydrazone (17) with HCl/EtOH proceeded rapidly to give six 1-methylindoles, ethyl 7-chloro (19), 6-chloro (22), and unsubstituted (24)-1-methylindole-2-car-boxylates, and dichloro derivatives (21, 23, and 26), whereas no indolization had occurred with the correspinding NH-hydrazone, as described in a previous paper. This result shows that the abnormal Fischer indolization of 2-chloro-phenylhydrazones with HCl/EtOH occurred in an ortho-C6 fashion, in the same manner as that of the corresponding 2-methoxyphenylhydrazones (1 and 2).The Fischer indolization of ethyl pyruvate 2-(2, 6-dichlorophenyl)methylhydrazone (18) with HCl/EtOH did not occur at all, whereas the reaction with ZnCl2/AcOH gave a low yield of ethyl 5, 7-dichloro-3-methylindole-2-carboxylate (36), which was formed by migration of the N-methyl group during Fischer indolization.
A facile access to benzo[d]thiazole-2(3H)-thiones and benzo[d]thiazol-2(3H)-ones has been developed through a temperature-controlled intermolecular [3 + 2] annulation of N,N-disubstituted arylhydrazines with CS2 in the presence of DMSO. This protocol can obviate the prefunctionalization of the starting materials. This direct C–S/C–N bond formation reaction was performed in the absence of any external
通过温度控制的 N,N 分子间 [3 + 2] 环化,开发了一种容易获得苯并[ d ]噻唑-2(3 H )-硫酮和苯并[ d ]噻唑-2(3 H )-酮的方法-在DMSO存在下用CS 2二取代的芳基肼。该协议可以避免起始材料的预功能化。这种直接的 C-S/C-N 键形成反应是在没有任何外部催化剂、过渡金属、碱、配体和氧化剂的情况下进行的,具有高步骤经济性。
Copper-Promoted Aerobic Oxidative [3+2] Cycloaddition Reactions of N,N-Disubstituted Hydrazines with Alkynoates: Access to Substituted Pyrazoles
A copper-promoted aerobic oxidative [3+2] cycloaddition reaction for the synthesis of various substituted pyrazoles from N,N-disubstituted hydrazines with alkynoates in the presence of bases is developed. This work involves a direct C(sp3)–H functionalization and the formation of new C–C/C–N bonds. In this strategy, inexpensive and easily available Cu2O serves as the promoter and air acts as the green
Direct use of methanol instead of formaldehyde or paraformaldehyde: Acceptorless dehydrogenative coupling for the synthesis of arylhydrazones catalyzed by a metal–ligand iridium bifunctional catalyst
作者:Beixuan Dong、Yiqian He、Xiangchao Xu、Peng Zhang、Qixun Shi、Feng Li
DOI:10.1016/j.jcat.2024.115685
日期:2024.10
The strategy of the synthesis of arylhydrazones via acceptorless dehydrogenative coupling of arylhydrazines with methanol was proposed and accomplished. In the presence of [Cp*Ir(2,2′-bpyO)(HO)] (0.5 mol %), a series of desirable products were obtained in high yields. It was found that functional groups in bpy are crucially important for the catalytic activity of iridium complexes. Furthermore, DFT