Base-Promoted Ecofriendly Synthesis of Trisubstituted Pyrazoles from α,β-Alkynyl N-Tosylhydrazones under Metal- and Solvent-Free Conditions
摘要:
A simple and green method is described for the synthesis of trisubstituted pyrazoles from ,-alkynyl N-tosylhydrazones under metal- and solvent-free conditions. Notably, only diisopropylamine is required as a promoter, and the reaction can be easily performed at room temperature and on a gram scale.
Zinc-promoted cyclization of tosylhydrazones and 2-(dimethylamino)malononitrile: an efficient strategy for the synthesis of substituted 1-tosyl-1H-pyrazoles
A Zn(OTf)2-promoted cyclization reaction of tosylhydrazones with 2-(dimethylamino)malononitrile has been successfully developed providing an efficient strategy for the synthesis of substituted 1-tosyl-1H-pyrazoles.
A New Synthesis of Pyrazoles through a Lewis Acid Catalyzed Union of 3-Ethoxycyclobutanones with Monosubstituted Hydrazines
作者:Gang Shan、Pengfei Liu、Yu Rao
DOI:10.1021/ol2002682
日期:2011.4.1
A new efficient and convenient approach toward the synthesis of pyrazoles is described. Through a Lewis acid catalyzed union of 3-ethoxycyclobutanones with monosubstituted hydrazines, a variety of pyrazole derivatives were prepared readily at ambient temperature with complete regioselectivity.
GRANDI R.; PAGNONI U. M.; TRAVE R., J. CHEM. RES. SYNOP., 1979, NO 10, 327, (M 3782-3788)
作者:GRANDI R.、 PAGNONI U. M.、 TRAVE R.
DOI:——
日期:——
Iridium‐Catalyzed Silylation of Five‐Membered Heteroarenes: High Sterically Derived Selectivity from a Pyridyl‐Imidazoline Ligand
作者:Caleb Karmel、Camille Z. Rubel、Elena V. Kharitonova、John F. Hartwig
DOI:10.1002/anie.201916015
日期:2020.4.6
The stericeffects of substituents on five-memberedrings are less pronounced than those on six-membered rings because of the difference in bond angles. Thus, the regioselectivities of reactions of five-membered heteroarenes that occur with selectivities dictated by stericeffects, such as the borylation of C-H bonds, have been poor in many cases. We report that the silylation of five-membered-ring
Base-Promoted Ecofriendly Synthesis of Trisubstituted Pyrazoles from α,β-Alkynyl N-Tosylhydrazones under Metal- and Solvent-Free Conditions
作者:Shufeng Chen、Ning Li、Baoguo Li
DOI:10.1055/s-0035-1561853
日期:——
A simple and green method is described for the synthesis of trisubstituted pyrazoles from ,-alkynyl N-tosylhydrazones under metal- and solvent-free conditions. Notably, only diisopropylamine is required as a promoter, and the reaction can be easily performed at room temperature and on a gram scale.