125732-48-1Relevant articles and documents
Dihydropyrans from 1,4-cycloaddition of enamines to arylmethylenepyrazolones. Polar character of the thermal rearrangement of the resulting cycloadducts
Abdel-Rahman,Abdel-Ghany
, p. 1281 - 1291 (2007/10/02)
The inverse electron demand hetero-Diels-Alder reaction of arylmethylenepyrazolones with enamines results in the selective formation of 3,4-dihydro-2H-pyran derivatives. These cycloadducts under thermodynamic conditions, are transformed via the zwitterion, which can be captured in the presence of tetracyanoethylene (TCE), as the more stable Michael-type adducts. The zwitterion could also be the intermediate for the cyclic adducts.
MICHAEL-TYPE ADDITION REACTIONS OF SOME ENAMINES TO ARYLIDENEPYRAZOLONES
Abdel-Rahman, M.,Abdel-Ghany, H.
, p. 1987 - 1996 (2007/10/02)
The reaction of the arylidenepyrazolones (1b-d) with 1-morpholinocyclohexene (E2) in refluxing acetonitrile leads to the less substituted alkylated enamines 3b-d.On the other hand, the more substituted alkylated enamines 2a-d are formed when 1a-d react under the same conditions with 1-piperidinocyclohexene (E1).The nature of the enamine in crucial.Nucleophilic attack of the enamine on the α,β-unsaturated carbonyl system of 1 gives rise to a zwitterionic intermediate which through α-proton loss leads to different Michael-type adducts depending on the enamine.