52188-06-4Relevant articles and documents
Br?nsted Acid Catalyzed Friedel–Crafts-Type Coupling and Dedinitrogenation Reactions of Vinyldiazo Compounds
Arman, Hadi,Dong, Kuiyong,Doyle, Michael P.,Wherritt, Daniel,Zheng, Haifeng
supporting information, p. 13613 - 13617 (2020/06/10)
The direct Friedel–Crafts-type coupling and dedinitrogenation reactions of vinyldiazo compounds with aromatic compounds using a metal-free strategy are described. This Br?nsted acid catalyzed method is efficient for the formation of α-diazo β-carbocations (vinyldiazonium ions), vinyl carbocations, and allylic or homoallylic carbocation species via vinyldiazo compounds. By choosing suitable nucleophilic reagents to selectively capture these intermediates, both trisubstituted α,β-unsaturated esters, β-indole-substituted diazo esters, and dienes are obtained with good to high yields and selectivity. Experimental insights implicate a reaction mechanism involving the selective protonation of vinyldiazo compounds and the subsequent release of dinitrogen to form vinyl cations that undergo intramolecular 1,3- and 1,4- hydride transfer processes as well as fragmentation.
Environment-friendly preparation method of ozagrel impurity II
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Paragraph 0052-0063, (2020/07/02)
The invention provides an environment-friendly preparation method of an ozagrel impurity II, and belongs to the technical field of preparation of drug impurity standard substances. The preparation method comprises the following steps: reacting 4-iodotolue
Consecutive Three-Component Coupling-Addition Synthesis of β-Amino Enoates and 3-Hydroxypyrazoles via Ethyl 3-Arylpropiolates
Niedballa, Jonas,Reiss, Guido J.,Müller, Thomas J. J.
supporting information, p. 5019 - 5024 (2020/07/24)
Two consecutive three-component syntheses furnishing β-amino enoates or 3-hydroxypyrazoles based upon the Sonogashira alkynylation of aryl iodides and ethyl propiolate were established in mostly excellent yields. The ethyl 3-arylpropiolate intermediates are Michael systems which are suited for concatenation with conjugate addition or cyclocondensation giving access to libraries of 21 different β-amino enoates and 17 different 3-hydroxypyrazoles. The rotational barrier of β-pyrrolidino enoates was assessed by studying the coalescence of pyrrolidinyl protons in VT-NMR spectra of electronically different substituted derivatives showing that the electronic substituent effect on the aryl group does not affect the height of the rotational barrier. This indicates that the substituents are essentially oriented orthogonally to the plane of the β-pyrrolidino enoates.
