A new efficient synthesis of pyrazoles from hydrazonoyl halides and β-oxo-phosphonates was written by Sun, Aixue;Ye, Jia-Hai;Yu, Haitao;Zhang, Wenchao;Wang, Xiaolong. And the article was included in Tetrahedron Letters in 2014.Safety of Ethyl 1,5-diphenyl-1H-pyrazole-3-carboxylate The following contents are mentioned in the article:
A new practical and efficient synthesis of 1,3,5-trisubstituted pyrazoles was developed by reacting of hydrazonoyl halides with β-oxo-phosphonates under mild conditions in good yields with excellent regioselectivity. This process employs an addition-elimination sequence. Wide scope, functional group compatibility was established. This study involved multiple reactions and reactants, such as Ethyl 1,5-diphenyl-1H-pyrazole-3-carboxylate (cas: 17355-75-8Safety of Ethyl 1,5-diphenyl-1H-pyrazole-3-carboxylate).
Ethyl 1,5-diphenyl-1H-pyrazole-3-carboxylate (cas: 17355-75-8) belongs to pyrazole derivatives. Pyrazole has two ring nitrogen atoms in which N1 is pyrrolic and N2 is pyridine-like. The N1 nitrogen is not reactive but is deprotonated in the presence of a base-forming anion. Pyrazoles can be selectively lithiated at different carbons and subsequently react with electrophiles depending on the substitution patterns.Safety of Ethyl 1,5-diphenyl-1H-pyrazole-3-carboxylate
Referemce:
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics