UNEXPECTED DIRECTION IN THE CYCLIZATION OF α,α'-DIAMINATED CYCLOPENTANONE WITH MALONIC DIALDEHYDE TETRAMETHYL ACETAL
DOI:
https://doi.org/10.1007/1163Keywords:
azodicarboxylic acid di-tert-butyl ester, cyclohexanone, cyclopentanone, 6, 7-dihydro-2H-cyclopenta[c]pyridazine-4-carbaldehyde, 3-hydroxy-2, 2-di(1H-pyrazol-1-yl)cyclopentanone, malonic dialdehyde tetramethyl acetal, 1-(2-oxocyclohexyl)-2-(3-oxoprop-1-en-1-yl)hydrazinecarboxylic acid tert-butyl ester, L-proline, pyrazoles, cyclization, stereoselective α-aminationAbstract
New compounds were unexpectedly discovered in a detailed study of the cyclization of α-aminated carbocyclic ketones with malonic dialdehyde tetramethyl acetal, in addition to the formation of the corresponding pyrazoles. In the case of cyclopentanone these new products are 6,7-dihydro-2H-cyclopenta[c]pyridazine-4-carbaldehyde and 3-hydroxy-2,2-di(1H-pyrazol-1-yl)cyclopentanone. For cyclohexanone, the intermediate in the cyclization to a pyrazole, namely, the tert-butyl ester of 1-(2-oxo-cyclohexyl)-2-(3-oxoprop-1-en-1-yl)hydrazinecarboxylic acid, was isolated.
Authors: A. A. Utkina, A. V. Kurkin, and M. A. Yurovskaya.
English Translation in Chemistry of Heterocyclic Compounds, 2012, 48 (6), pp 892-896
