Radikalreaktionen an N-Heterocyclen. XI [1] Reaktionen von 3-Methyl-pyrazolin-5-onen mit Phenoxyl-Radikalen
作者:Manfred Schulz、Michael Meske
DOI:10.1002/prac.19933350706
日期:——
Pyrazolin-5-ones (3a-4) were oxidized with 2,4,6-trisubstituted phenoxy radicals (2a-d) to the corresponding radicals (4a-i), which dimerised or combined with phenoxy radical (2a) depending on the R1- and R4-substituents in (3). In the case of 3-methyl-1-phenyl-pyrazolin-5-one (3f) the primary radical combination products were not found, but the corresponding quinone methide (17) and the o-phenol derivative (18) were isolated. Products and yields have been investigated as a function of mol ratio substrate: oxidant and solvent. The radical combination products (7-10) could de-tertbutylated in the presence of aluminium chloride or in the presence of trifluoroarcetic acid, forming heterocyclic substituted phenols (21) and (22).