749923-92-0Relevant academic research and scientific papers
Chemistry of diazopolycarbonyl compounds: VIII. Synthesis of nitrogen-containing heterocycles via transformations of substituted 2-diazopentane-1,3,5-triones
Kutkovaya,Vyaznikova,Zalesov
, p. 1644 - 1648 (2003)
Ethyl 5-aryl-2-diazo-3,5-dioxopentanoates and 1,5-diaryl-2-diazopentane-1, 3,5-triones are partially enolized in solutions. By O-methylation of enol forms of diazo esters with diazomethane ethyl 5-aryl-2-diazo-5-methoxy-3-oxopent-4- enoates were prepared. Concurrently with the O-methylation the diazo esters undergo heterocyclization into 3,5-disubstituted 4-hydroxypyrazoles which under the reaction condition suffer O- and N-methylation by excess diazomethane. 3,5-Diaroyl-4-hydroxypyrazoles were also obtained from diazopentanetriones but here triethylamine served as the cyclization reagent.
