3-Alkenyl-5-chloropyrazoles: expedient synthesis via heterocyclization of 1,1-dichloro-4-halo-1-alken-3-ones with hydrazines
摘要:
Synthesis of hard-to-reach 5-chloro-3-alkenylpyrazoles was developed via heterocyclization of alkyl-, benzyl- or dialkylhydrazines with 1,1-dichloro-4-halo-1-alken-3-ones obtained from haloacyl chlorides and vinylidene chloride. The reaction process includes the formation of intermediate 5-chloro-3-(1-haloalkyl)pyrazoles followed by dehydrohalogenation. (C) 2011 Elsevier Ltd. All rights reserved.
Directed synthesis of 3-(2,2-dichlorocyclopropyl)pyrazoles
作者:V. A. Kobelevskaya、A. V. Popov、A. Ya. Nikitin、G. G. Levkovskaya
DOI:10.1134/s1070428017010298
日期:2017.1
1-Alkyl-3-(2,2-dichlorocyclopropyl)-1H-pyrazoles have been synthesized by cyclopropanation of the corresponding 3-vinylpyrazoles with dichlorocarbene generated from chloroform or sodium trichloroacetate and tested for insecticidal activity.
作者:Alexandr V. Popov、Valentina A. Kobelevskaya、Lyudmila I. Larina、Galina G. Levkovskaya
DOI:10.1016/j.mencom.2017.03.024
日期:2017.3
The Vielsmeier–Haack formylation of 5-chloro-3-alkenylpyrazoles proceeds at the olefinic double bond and affords (2E)-3-(5-chloro-1H-pyrazol-3-yl)prop-2-enals.
Selective synthesis of 3-[1-(organylsulfanyl)ethyl]- and 3-[2-(organylsulfanyl)ethyl]-5-chloro-1H-pyrazoles
作者:D. O. Samultsev、E. V. Rudyakova、G. G. Levkovskaya
DOI:10.1134/s1070428012100259
日期:2012.10
Synthesis of previously unknown 3,3′-linearly linked sulfur- and selenium-containing bispyrazoles by reactions of 3-alkenyl-5-chloropyrazoles with bischalcogenols
作者:E. V. Rudyakova、D. O. Samultsev、E. P. Levanova、G. G. Levkovskaya
DOI:10.1134/s1070428013050175
日期:2013.5
By reactions of 3-alkenyl-5-chloropyrazoles with appropriate dichalcogenols the fi rst specimens were obtained of previously unknown 3,3'-linearly linked bispyrazoles containing in the alkyl chain of the linker two heteroatoms, sulfur or selenium. 3-Vinyl-5-chloropyrazoles react with 1,3-propanedithiol, 2-hydroxy-1,3-propanedithiol, and 2-hydroxy-1,3-propanediselenol under UV irradiation and heating at 60A degrees C over 8 h affording products of the addition against Markovnikoff rule. The radical addition of 1,3-propanedithiol to 3-isopropenyl-5-chloropyrazole required a longer time, 15 h.