22896-71-5Relevant academic research and scientific papers
Organocatalytic Enantioselective Aminoalkylation of 5-Aminopyrazole Derivatives with Cyclic Imines
Carceller-Ferrer, Laura,González del Campo, Aleix,Vila, Carlos,Blay, Gonzalo,Mu?oz, M. Carmen,Pedro, José R.
supporting information, p. 7450 - 7454 (2020/11/30)
In this communication, an efficient asymmetric aminoalkylation of 5-aminopyrazole derivatives with cyclic benzoxathiazine 2,2-dioxides catalyzed by a quinine-derived squaramide in dichloromethane has been established. This is the first example of 5-aminopyrazole derivatives in asymmetric catalysis. A variety of chiral sulfamidates bearing an aminopyrazole moiety were obtained in good yields (up to 98 %) and moderate to excellent enantioselectivities (up to 99 %ee).
Correlation of spectroscopically determined ligand donor strength and nucleophilicity of substituted pyrazoles
Bernhammer, Jan Christopher,Huynh, Han Vinh
experimental part, p. 8600 - 8608 (2012/10/07)
The relative ligand donor strengths of 10 pyrazole-derived ligands has been determined with great accuracy, making use of the interdependence between the donor strength of the co-ligand and the 13C NMR chemical shift of the iPr2-bimy carbene signal in trans-[PdBr2( iPr2-bimy)L] complexes (iPr2-bimy = 1,3-diisopropylbenzimidazolin-2-ylidene; L = pyrazole-derived ligand). Even subtle variations in the substitution pattern of the pyrazole backbone up to three bonds away from the coordinating nitrogen could be detected reliably using this methodology. Alkylation experiments conducted on the pyrazoles using electrophiles of varied reactivity (ethyl bromide, ethyl iodide, and trimethyloxonium tetrafluoroborate) served as a benchmark to rank the pyrazoles in three groups of gradually increasing nucleophilicity, which correlated well with their determined donor strength.
Synthesis and application of a fluorous Lawesson's reagent: Convenient chromatography-free product purification
Kaleta, Zoltan,Tarkanyi, Gabor,Goemoery, Agnes,Kalman, Ferenc,Nagy, Tamas,Soos, Tibor
, p. 1093 - 1095 (2007/10/03)
A fluorous analogue of Lawesson's reagent for thionation of carbonyl compounds has been developed and its use demonstrated on a series of amides, esters, and ketones. The separation of the Lawesson's reagent-derived byproducts can be achieved by a simple fluorous solid-phase extraction.
One-pot synthesis of 5-(substituted-amino)pyrazoles
Dodd, Dharmpal S.,Martinez, Rogelio L.
, p. 4265 - 4267 (2007/10/03)
An efficient and mild one-pot synthesis of substituted 5-alkylamino and/or 5-(arylamino)pyrazoles is described. A suitably decorated β-ketoamide, an aryl or alkyl hydrazine and Lawesson's reagent are suspended in THF/Py and gently heated to yield the requisite 5-aminopyrazoles.
