Direct N-heterocyclization of hydrazines to access styrylated pyrazoles: synthesis of 1,3,5-trisubstituted pyrazoles and dihydropyrazoles
作者:Vunnam Venkateswarlu、Jaspreet Kour、K. A. Aravinda Kumar、Praveen Kumar Verma、G. Lakshma Reddy、Yaseen Hussain、Aliya Tabassum、Shilpi Balgotra、Sorav Gupta、Abhinandan D. Hudwekar、Ram A. Vishwakarma、Sanghapal D. Sawant
DOI:10.1039/c8ra04550j
日期:——
microwave-assisted method has been developed for the synthesis of tri-substituted pyrazoles via direct N-heterocyclization of hydrazines with metal-acetylacetonate and -dibenzylideneacetonate without using any base or additives. Most importantly, the synthesis of 1-aryl-5-phenyl-3-styryl-1H-pyrazoles was achieved in a single step using hydrochloride salt of various phenylhydrazines and this is the first
Synthesis of Unsymmetrical 2,6-Diarylanilines by Palladium-Catalyzed C–H Bond Functionalization Methodology
作者:Se Hun Kwak、Nurbey Gulia、Olafs Daugulis
DOI:10.1021/acs.joc.8b00659
日期:2018.5.18
3,5-Dimethylpyrazole was employed as a monodentate directing group for palladium-catalyzed ortho-sp2 C–H arylation with aryl iodides. The reaction shows good functional group tolerance and outstanding selectivity for mono-ortho-arylation. Ozonolysis of ortho-arylated arylpyrazoles gave acylated biphenylamines that were further arylated to afford unsymmetrically substituted 2,6-diarylacetanilides.
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
An environmentally benign and efficient synthesis of 4‐Selanylpyrazoles catalyzed by haloid salts in water
作者:Yingguo Fang、Junxing Wang、Yuhong Liu、Jie Yan
DOI:10.1002/aoc.4921
日期:2019.6
An environmentally benign procedure is developed for the preparation of 4‐selanylpyrazoles from pyrazoles and diselenides. Using haloid salts as catalysts and H2O2 as oxidant, this catalytic protocol is convenient in water at room temperature under open‐air condition, and is suitable for a wide variety of starting materials and provides a series of 4‐selanylpyrazoles in good yields. A plausible catalytic
开发了一种环境友好的程序,用于从吡唑和二硒化物制备4-硒基吡唑。使用卤素盐作为催化剂,H 2 O 2作为氧化剂,该催化方案在室温,露天条件下的水中非常方便,适用于多种起始原料,并提供了一系列产率高的4-硒基吡唑。推测可能的催化亲电取代机理。
Transition metal containing ionic liquid-assisted one-pot synthesis of pyrazoles at room temperature
作者:Manashjyoti Konwar、Hanan M F Elnagdy、Praveen Singh Gehlot、Nageshwar D Khupse、Arvind Kumar、Diganta Sarma
DOI:10.1007/s12039-019-1659-9
日期:2019.8
AbstractThe feasible and one of the green ways to synthesize organic compounds especially pyrazole and its derivatives are systematically presented. The one-pot synthesis of pyrazole was achieved by condensation of various hydrazines and 1,3-diketone derivatives at roomtemperatureusing transition metal-based ionicliquids. Herein, the unique combination of Fe(III) with ionicliquid is explored and utilized