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. Name: Ethyl 4-pyrazolecarboxylate.
Haydl, Alexander M.;Hilpert, Lukas J.;Breit, Bernhard research published 《 Regioconvergent and Enantioselective Rhodium-Catalyzed Hydroamination of Internal and Terminal Alkynes: A Highly Flexible Access to Chiral Pyrazoles》, the research content is summarized as follows. In the presence of (cyclooctadiene)rhodium(I) chloride dimer, a nonracemic ferrocenyldiphosphine monoxide, and pyridine p-toluenesulfonate (PPTS), 1-aryl-1-propynes such as RCCMe (R = Ph, 4-MeC6H4, 4-F3CC6H4, 4-PhC6H4, 2-naphthyl, 4-FC6H4, 4-ClC6H4, 4-BrC6H4, 4-MeCOC6H4, 4-O2NC6H4, PinB; PinB = 4,4,5,5-tetramethyl-1,3-dioxo-2-borolan-2-yl), phenylallene, and selected 1-aryl-2-propynes underwent chemoselective, regioselective, and enantioselective addition reactions with 1H-pyrazoles to yield nonracemic N1-allylic pyrazoles such as I (R = Ph, 4-MeC6H4, 4-F3CC6H4, 4-PhC6H4, 2-naphthyl, 4-FC6H4, 4-ClC6H4, 4-BrC6H4, 4-MeCOC6H4, 4-O2NC6H4, PinB) in 65-97% yields, in 68:32->99:1 regioselectivities, and in 80:20-97.5:2.5 er (or, for nonracemic pyrazoles, 82:18 or 85:15 dr). The method tolerated a variety of functional groups in the alkyne and pyrazole components. The structure of a phenylallylated stanozolol was determined by X-ray crystallog.
Name: Ethyl 4-pyrazolecarboxylate, 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