The use of enaminones and enamines as effective synthons for MSA-catalyzed regioselective synthesis of 1,3,4-tri- and 1,3,4,5-tetrasubstituted pyrazoles
In the present work, an efficient regioselectivesynthesis of 1,3,4-tri- and 1,3,4,5-tetrasubstituted pyrazoles via a methanesulfonic acid (MSA)-catalyzed reaction of hydrazones with enaminones or enamines is reported. Mechanistically, the formation of the title compounds involves the [2+3] cycloaddition of hydrazones with enaminones or enamines followed by aromatization with acid and oxygen. This
DMSO as a C<sub>1</sub> Source for [2 + 2 + 1] Pyrazole Ring Construction via Metal-Free Annulation with Enaminones and Hydrazines
作者:Haijin Guo、Lihong Tian、Yunyun Liu、Jie-Ping Wan
DOI:10.1021/acs.orglett.1c03879
日期:2022.1.14
between enaminones, hydrazines, and dimethyl sulfoxide (DMSO) for the synthesis of 1,4-disubstitutedpyrazoles catalyzed by molecular iodine in the presence of Selectfluor has been realized. DMSO plays a dual role as the C1 source and the reaction medium. In addition, the synthesis of 1,3,4-trisubstituted pyrazoles using aldehydes as alternative C1 building blocks has also been achieved.
已经实现了烯胺酮、肼和二甲亚砜 (DMSO) 之间的级联反应,用于在 Selectfluor 存在下由分子碘催化合成 1,4-二取代吡唑。DMSO作为C 1源和反应介质发挥双重作用。此外,还实现了使用醛作为替代 C 1结构单元的 1,3,4-三取代吡唑的合成。
Coutouli-Argyropoulou, E.; Thessalonikeos, E., Journal of Heterocyclic Chemistry, 1991, vol. 28, # 2, p. 429 - 432
作者:Coutouli-Argyropoulou, E.、Thessalonikeos, E.
DOI:——
日期:——
COUTOULI-ARGYROPOULOU, E.;THESSALONIKEOS, E., J. HETEROCYCL. CHEM., 28,(1991) N, C. 429-432