73130-07-1Relevant academic research and scientific papers
Palladium-Catalyzed Pyrazole-Directed sp3 C?H Bond Arylation for the Synthesis of β-Phenethylamines
Gulia, Nurbey,Daugulis, Olafs
supporting information, p. 3630 - 3634 (2017/03/21)
We have developed a method for palladium-catalyzed, pyrazole-directed sp3 C?H bond arylation by aryl iodides. The reaction employs a Pd(OAc)2 catalyst at 5–10 mol % loading and silver(I) oxide as a halide-removal agent, and it proceeds in acetic acid or acetic acid/hexafluoroisopropanol solvent. Ozonolysis of the pyrazole moiety affords pharmaceutically important β-phenethylamines.
Cu-promoted sydnone cycloadditions of alkynes: Scope and mechanism studies
Comas-Barcel?3, Jffllia,Foster, Robert S.,Fiser, B??la,Gomez-Bengoa, Enrique,Harrity, Joseph P. A.
supporting information, p. 3257 - 3263 (2015/03/05)
Cu salts have been found to promote the cycloaddition reaction of sydnones and terminal alkynes, providing significant reduction in reaction times. Specifically, the use of Cu(OTf)2 is found to provide 1,3-disubstituted pyrazoles, whereas simpl
Efficient one-pot synthesis of substituted pyrazoles
Tang, Meng,Zhang, Fu-Min
, p. 1427 - 1433 (2013/02/25)
An efficient, one-pot synthesis of substituted pyrazoles from enones, hydrazides, and halides was developed. In comparison with the classical Knorr pyrazole synthesis, this methodology gave a different type of product (R 3≥R5). A range of substituted pyrazoles were prepared in good to high yields with complete regioselectivity.
A new germanium-based linker for solid phase synthesis of aromatics: Synthesis of a pyrazole library
Spivey, Alan C.,Diaper, Christopher M.,Adams, Harry,Rudge, Andrew J.
, p. 5253 - 5263 (2007/10/03)
An efficient synthesis of chlorogermane linker 12 is described. Economic introduction of germanium into this linker is accomplished by insertion of dichlorogermylene [from germanium(IV) chloride] into the homobenzylic C-Cl bond of 4-(2-chloroethyl)phenol 1. Using linker 12, transmetalation with lithiated 4-acetophenone, 3-acetophenone, and 4-(4'methoxy)biphenyl followed by Mitsunobu-type coupling to Argogel gives functionalized resins 14, 16, and 18, respectively. Treatment of resin 18 with TFA, ICl, Br2, or NCS effects clean ipso-degermylation releasing biphenyls 19-22, respectively. Resins 14 and 16 are employed for the parallel synthesis of a library of pyrazoles by enaminone formation (using Bredereck's reagent), condensative ring-closure (using a series of monosubstituted hydrazines), and cleavage (using TFA and Br2). Analysis of this library reveals the influence of the hydrazine substituent on both the regioselectivity of ring-closure and the propensity for electrophilic substitution at the 4-position of the pyrazoles during ipso-degermylative cleavage.
