125732-52-7

Upstream product

• 132603-48-6 E-1-phenyl-3-methyl-4-<(4-nitrophenyl)methylene>-5-pyrazolone 
• 670-80-4 4-cyclohexen-1-ylmorpholine 
• 135763-50-7 3-Methyl-8a-morpholin-4-yl-4-(4-nitro-phenyl)-1-phenyl-1,4,4a,5,6,7,8,8a-octahydro-chromeno[2,3-c]pyrazole 
• 670-54-2 ethenetetracarbonitrile 

Relevant academic research and scientific papers

Dihydropyrans from 1,4-cycloaddition of enamines to arylmethylenepyrazolones. Polar character of the thermal rearrangement of the resulting cycloadducts

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

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.