Approach to the library of fused pyridine-4-carboxylic acids by Combes-type reaction of acyl pyruvates and electron-rich amino heterocycles was written by Volochnyuk, Dmitriy M.;Ryabukhin, Sergey V.;Plaskon, Andrey S.;Dmytriv, Yuri V.;Grygorenko, Oleksandr O.;Mykhailiuk, Pavel K.;Krotko, Dmitriy G.;Pushechnikov, Alexei;Tolmachev, Andrey A.. And the article was included in Journal of Combinatorial Chemistry in 2010.Formula: C8H15N3 This article mentions the following:
A library of fused pyridine-4-carboxylic acids (including pyrazolo[3,4-b]pyridines, isoxazolo[5,4-b]pyridines, furo[2,3-b]pyridines, thieno[2,3-b]pyridines, and pyrido[2,3-d]pyrimidines) was generated by Combes-type reaction of acyl pyruvates and electron-rich amino heterocycles followed by hydrolysis of the ester. The library members were also demonstrated to undergo the standard combinatorial transformations including amide coupling and esterification, as well as less common heterocyclizations to 1,2,4-triazoles and 1,2,4-oxadiazoles. In the experiment, the researchers used many compounds, for example, 1-(tert-Butyl)-3-methyl-1H-pyrazol-5-amine (cas: 141459-53-2Formula: C8H15N3).
1-(tert-Butyl)-3-methyl-1H-pyrazol-5-amine (cas: 141459-53-2) 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. The pyrazole ring is resistant to oxidation and reduction but the groups, such as alkyl and formyl attached to the ring, are oxidized to respective acids. Only electrolytic oxidation, ozonolysis, and a strong base cause ring opening.Formula: C8H15N3
Referemce:
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics