53645-68-4Relevant academic research and scientific papers
Palladium-catalyzed regioselective direct C–H arylation of?pyrazolo[3,4-d]pyrimidines
El Hafi, Mohamed,Naas, Mohammed,Loubidi, Mohammed,Jouha, Jabrane,Ramli, Youssef,Mague, Joel T.,Essassi, El Mokhtar,Guillaumet, Gérald
, p. 927 - 933 (2017/09/06)
Nitrogenous bicycles are an apparently endless field of organic and biological research. In this study, we disclose an efficient pathway to the synthesis of the pyrazolo[3,4-d]pyrimidine scaffold in three steps from allopurinol. This key intermediate was engaged in the first example of regioselective C–H arylation catalyzed by palladium to access a library of 3-substituted-1-methyl-4-phenyl-1H-pyrazolo[3,4-d]pyrimidines.
Aryl Coupling Reactions of Pyrazolopyrimidin-4-yl Radicals
Press, Jeffery B.,Eudy, Nancy H.,Morton, George O.
, p. 4605 - 4611 (2007/10/02)
4-Arylpyrazolopyrimidines (4) were the subjects of a synthetic investigation in order to evaluate their biological activity.Attempts to prepare 4 from 4-aminopyrazolopyrimidines (5) via classical Gomberg-Bachmann-Hey aryl coupling conditions failed.Conversion of 5 to 4 was accomplished by diazotiazation of 5 using alkyl nitrites with an acid catalyst in aromatic solvents.Isomer distribution of the aryl-coupled products 4 was that predicted for a radical intermediate (ortho > meta ca. para); isomer structures were assigned by a detailed 1H NMR analysis.Unusual fragmentation products 17 and 18 were isolated during the course of investigations.These oxadiazoles probably arise from collapse of intermediate pyrazolopyrimidin-4-yl radicals 15.
