‘One-pot’ synthesis of 4-substituted 1,5-diaryl-1H-pyrazole-3-carboxylates via lithium tert-butoxide-mediated sterically hindered Claisen condensation and Knorr reaction was written by Jiang, Jian-An;Huang, Wei-Bin;Zhai, Jiao-Jiao;Liu, Hong-Wei;Cai, Qi;Xu, Liu-Xin;Wang, Wei;Ji, Ya-Fei. And the article was included in Tetrahedron in 2013.Quality Control of Ethyl 1,5-diphenyl-1H-pyrazole-3-carboxylate The following contents are mentioned in the article:
A concise ‘one-pot’ synthesis of a variety of 4-substituted 1,5-diaryl-1H-pyrazole-3-carboxylates has been developed in moderate to good yields with excellent regioselectivity. Less cost lithium tert-butoxide has been identified as a base for sterically hindered Claisen condensation to efficiently generate the labile 3-substituted 4-aryl-2,4-diketoesters. Furthermore, extensive studies lead to a ‘one-pot’ process by combination of the Claisen condensation and the Knorr reaction for the synthesis of highly valuable 4-substituted 1,5-diaryl-1H-pyrazole-3-carboxylates. This study involved multiple reactions and reactants, such as Ethyl 1,5-diphenyl-1H-pyrazole-3-carboxylate (cas: 17355-75-8Quality Control 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. Pyrazoles, a five-membered heterocycle containing two adjacent nitrogen atoms, are the core structures found in a number of molecules that possess a wide range of pharmaceutical and agricultural activities. Protonation of pyrazole in strong acid leads to pyrazolium cations, which undergo electrophilic substitution preferentially at C3 rather than C4. The pyrazole anion is not reactive toward nucleophiles but is mostly reactive to electrophiles.Quality Control of Ethyl 1,5-diphenyl-1H-pyrazole-3-carboxylate
Referemce:
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics