25142-45-4Relevant articles and documents
Highly Efficient Cycloaddition Reaction of 1,3-Diynes with Sodium Azide: A New Way to 5-Substituted-4-acetylene-1H-1,2,3-triazoles
Tang, Jia-Liang,Ming, Ling,Zhao, Xiao-Ming
, p. 1367 - 1370 (2016)
A cycloaddition reaction of a range of 1,3-diynes with sodium azide has been realized, which provided 5-substituted-4-acetylene-1H-1,2,3-triazoles in 75–99% yields. The chemical structures of the new compounds 3 are established by IR, NMR, Mass, and HRMS.
Diazophosphonates: Effective Surrogates for Diazoalkanes in Pyrazole Synthesis
Green, Michael T.,Hayes, Christopher J.,Inman, Martyn,Lewis, William,Moody, Christopher J.,Nicolle, Simon M.,Ruffell, Katie,Smith, Frances R.
, p. 13703 - 13708 (2021/09/09)
Diazophosphonates, readily prepared from α-ketophosphonates by oxidation of the corresponding hydrazones in batch or in flow, are useful partners in 1,3-dipolar cycloaddition reactions to alkynes to give N-H pyrazoles, including the first intramolecular examples of such a process. The phosphoryl group imbues a number of desirable properties into the diazo 1,3-dipole. The electron-withdrawing nature of the phosphoryl stabilizes the diazo compound making it easier to handle, whilst the ability of the phosphoryl group to migrate readily in a [1,5]-sigmatropic rearrangement enables its transfer from C to N to aromatize the initial cycloadduct, and hence its facile removal from the final pyrazole product. Overall, the diazophosphonate acts as a surrogate for the much less stable diazoalkane in cycloadditions, with the phosphoryl group playing a vital, but traceless, role. The cycloaddition proceeds more readily with alkynes bearing electron-withdrawing groups, and is regiospecific with asymmetrical alkynes. The potential of diazophosphonates for use in bioorthogonal cycloadditions is demonstrated by their facile addition to strained alkynes.
Method used for preparing pyrazole compounds in recoverable solvent
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Paragraph 0031; 0032, (2017/10/07)
The invention provides a method used for preparing pyrazole compounds in a recoverable solvent. According to the method, 1,3-diyne and hydrazine are taken as raw materials, and DMSO/H2O is taken as a reaction solvent. The method comprises following advantages: reaction steps are few; raw materials are cheap; the solvent can be recycled conveniently; reaction conditions are mild; the method is friendly to the environment; product yield is high; purity is high; the obtained product is capable of satisfying requirements on quality of drug intermediates; an ideal approach is provided for industrialized production; and application prospect is promising.