Pyrazole is an organic compound with the formula C3H3N2H. It is a heterocycle characterized by a 5-membered ring of three carbon atoms and two adjacent nitrogen atoms, which are in ortho-substitution. 37622-90-5, formula is C6H8N2O2, Name is Ethyl 4-pyrazolecarboxylate. Pyrazoles are a class of compounds that have the ring C3N2 with adjacent nitrogen atoms.Notable drugs containing a pyrazole ring are celecoxib (celebrex) and the anabolic steroid stanozolol. Application In Synthesis of 37622-90-5.
Testa, Christelle;Roger, Julien;Scheib, Stephanie;Fleurat-Lessard, Paul;Hierso, Jean-Cyrille research published 《 Palladium-Catalysed C-H Bond Electrophilic Fluorination of Highly Substituted Arylpyrazoles: Experimental and DFT Mechanistic Insights》, the research content is summarized as follows. A general protocol for palladium-catalyzed C-H mono- and di-fluorination of highly substituted arylpyrazoles is reported. Coupling pathways and substrate limitations are discussed in the light of complementary mechanistic exptl. and d. functional theory (DFT) studies. The mono- and di-ortho-fluorination of arylpyrazoles having substituted pyrazole groups and ortho-, meta-, or para-substituted arene moieties is achieved. Various pyrazole groups can efficiently promote the direct C-H activation/fluorination of substrates bearing valuable reactive ester, cyano, halide and nitro functions. The presence of methoxy, Me and trifluoromethyl is tolerated on the pyrazole directing groups. However, steric substituent effects have a marked influence which is evidenced by calculations DFT modeling suggested also a previously unseen outer-sphere oxidative addition of N-fluorobenzenesulfonimide (NFSI) to Pd(II) as an alternative mechanism to the commonly assumed Pd(II)/Pd(IV) process. This unprecedented proposal, which is supported by the mass spectrometry identification of a key Pd(II) monomer under the stoichiometric conditions deserves more attention. The influence of elaborate highly substituted directing groups on the course of Pd-catalyzed fluorination has generally received limited attention although this question has a crucial synthetic utility; herein, appropriate conditions for isolating pure products are reported.
Application In Synthesis of 37622-90-5, Ethyl 4-pyrazolecarboxylate, also known as Ethyl pyrazole-4-carboxylate, is a useful research compound. Its molecular formula is C6H8N2O2 and its molecular weight is 140.14 g/mol. The purity is usually 95%.
Ethyl pyrazole-4-carboxylate is a low yield, transition metal salt that is used in the synthesis of pyrazoles. It can be synthesized by the reaction of sodium ethoxide with ethyl chloroformate and a Grignard reagent. Sodium ethoxide is added to a suspension of sodium chloride and dried ethyl chloroformate, followed by addition of magnesium turnings. The mixture is refluxed for one hour, cooled, and filtered to give crystals. Ethyl pyrazole-4-carboxylate is used in the preparation of ethyl esters from aliphatic alcohols by reacting with boron trichloride or phosphorus pentachloride. It participates in certain chemical reactions as a byproduct and can damage equipment during chemical reactions. The yield of this compound can be increased by using an excess amount of Grignard reagent or adding hexamethylenetetramine to the reaction mixture, 37622-90-5.
Referemce:
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics