27666-83-7Relevant academic research and scientific papers
Choline hydroxide promoted sustainable one-pot three-component synthesis of 1H-pyrazolo[1,2-a]pyridazine-2-carbonitriles under solvent-free conditions
Vajekar, Shailesh N.,Shankarling, Ganapati S.
, p. 1147 - 1158 (2020)
A sustainable one-pot three-component synthesis of novel 1H-pyrazolo[1,2-a]pyridazine-2-carbonitrile derivatives employing a highly efficient, biodegradable, and recyclable choline hydroxide catalyst under solvent-free conditions is demonstrated. The salient features of this protocol are simple workup, mild reaction conditions, short reaction time (10 min), excellent yields (up to 97%), high atom economy, column chromatography-free protocol, and eco-friendliness. Interestingly, the choline hydroxide was recycled up to five cycles without any considerable loss of efficiency. The structures of the products were deduced by their 1H NMR, 13C NMR, and HRLC-MS spectra.
New heterocycles of 2,3-diaryl-substituted maleic hydrazides
Shih, Hsiencheng,Shih, Renshuay J.,Carson, Dennis A.
experimental part, p. 1243 - 1250 (2012/01/04)
2,3-Diaryl-substituted maleic anhydrides were prepared by a modified one-pot synthesis of Perkin condensation using mixed sodium salts of arylglyoxylic acid and arylacetic acid with acetic anhydride in 1,4-dioxane. The treatment of these anhydrides with ammonium bicarbonate, or methanolic hydrazine, offered the corresponding 2,3-diaryl-substituted maleimides and maleic hydrazides (4,5-diaryl-substituted 1,2-dihydropyridazine-3,6-dione), respectively. Evidence obtained from NMR, UV, and mass spectra suggest that 2,3-diaryl-substituted maleic hydrazides do not exhibit monolactim forms. Ring contraction of the diaryl-substituted maleic hydrazide by nitrosation led to the formation of the corresponding maleimide. Interconversion between the corresponding maleic hydrazide and maleimide was observed following equilibrium reaction. Our experiment proposes that the chemistry of 2,3-diaryl-substituted maleic hydrazides rarely involves the function of ethylene moiety and resembles that of succinic hydrazine. Copyright
