1,3-Diketones from Acid Chlorides and Ketones: A Rapid and General One-Pot Synthesis of Pyrazoles
作者:Stephen T. Heller、Swaminathan R. Natarajan
DOI:10.1021/ol060570p
日期:2006.6.1
[reaction: see text] 1,3-Diketones were synthesized directly from ketones and acidchlorides and were then converted in situ into pyrazoles by the addition of hydrazine. This method is extremely fast, general, and chemoselective, allowing for the synthesis of previously inaccessible pyrazoles and synthetically demanding pyrazole-containing fused rings.
One-Pot Coupling–Coupling–Cyclocondensation Synthesis of Fluorescent Pyrazoles
作者:Alissa C. Götzinger、Florian A. Theßeling、Corinna Hoppe、Thomas J. J. Müller
DOI:10.1021/acs.joc.6b01326
日期:2016.11.4
ondensation syntheses of pyrazoles and pyrimidines were developed by taking advantage of the provisional, sequentially Pd-catalyzed one-pot generation of alkynones from aryl iodides, ethynylmagnesium bromide, and acid chlorides. This one-pot methodology allows the concise, diversity-oriented generation of a set of donor-, acceptor-, and donor–acceptor-substituted pyrazoles, which are interesting fluorophores
Preparation of 3,5-Disubstituted Pyrazoles and Isoxazoles from Terminal Alkynes, Aldehydes, Hydrazines, and Hydroxylamine
作者:Ryo Harigae、Katsuhiko Moriyama、Hideo Togo
DOI:10.1021/jo4027116
日期:2014.3.7
provided the corresponding 3,5-disubstituted pyrazoles or isoxazoles in good yields with high regioselectivity, through the formations of propargyl secondary alkoxides and α-alkynyl ketones. The present reactions are one-pot preparation of 3,5-disubstituted pyrazoles from terminal alkynes, aldehydes, molecular iodine, and hydrazines, and 3,5-disubstitutedisoxazolesfrom terminal alkynes, aldehydes
Aluminum Chloride Mediated Reactions of N-Alkylated Tosylhydrazones and Terminal Alkynes: A Regioselective Approach to 1,3,5-Trisubstituted Pyrazoles
作者:Meng Tang、Yun Wang、Hu Wang、Yuanfang Kong
DOI:10.1055/s-0035-1561646
日期:——
Abstract Aluminum chloridemediated reactions of N-alkylated tosylhydrazones and terminal alkynes are reported. The protocol is applied to a wide range of substrates, and demonstrates excellent functional group tolerance. A series of 1,3,5-trisubstituted pyrazoles is prepared in good to high yields with complete regioselectivity. Aluminum chloridemediated reactions of N-alkylated tosylhydrazones and
Visible-Light Photocatalytic Aerobic Annulation for the Green Synthesis of Pyrazoles
作者:Ya Ding、Te Zhang、Qiu-Yun Chen、Chunyin Zhu
DOI:10.1021/acs.orglett.6b01867
日期:2016.9.2
A selective and high yielding synthesis of polysubstituted pyrazoles through a VLPC (visible light photoredox catalysis)-promoted reaction of hydrazine with Michael acceptors is reported. The method employs very mild reaction conditions and usesair as the terminal oxidant, which makes the process environmentally benign. Different types of Michael acceptors with various substituents can undergo the