2- oxoindolin-3-ylidenes

In another failed approach, addition of 1-pyrrolidinocyclohexene 32 to ( )-( l-melhyl-2-oxoindolin-3-ylidene)acetophenone 31, followed by acid hydrolysis, could be controlled simply by changes in the reaction temperature, and was found to give diastereoselectively compounds 33 or 34. The latter compound was shown by NMR and X-ray diffraction data to have the suitable geometry to allow the creation of the crucial bond between the position adjacent to the cyclohexanone carbonyl and the oxindole C-4 position. 

Scheme 6 Studies on an approach to welwistatin based on an enamine addition onto a (2-oxoindolin-3-ylidene)acetophenone derivative...

Zwitterionic intermediates (50) have been isolated as stable products in the reaction of 2-oxoindolin-3-ylidene derivatives with enediamines and their structure confirmed by X-ray analysis99 (Scheme 34). 

Scheme 7.80 NHC-catalyzed asymmetric formal Diels-Alder reaction of a-chloroaldehydes with 2-oxoindolin-3-ylidenes reported by Zhong.

Table 8.5 Comparative study for synthesis of 2-(2-oxoindolin-3-ylidene)hydrazineearbothio-amide under different reaetion eonditions...

Yan Z, Sun B, Li Y (2013) Novel stable (3E,7E)-3,7-bis(2-oxoindolin-3-ylidene)benzo[l,2-h 4,5-6 ]difuran-2,6(3H,7H)-dione based donor-acceptor polymer semiconductors for n-type organic thin film transistors. Chem Commun 49 3790-3792... 

Z)-5-Nitro-5 -(2-(5-iiitro-2-oxoindolin-3-ylidene)hydrazinyl)-l, 2 -dihydrospiro[indoline-3,3 -pyrazol]-2-one (4b) Mustard powder mp up 300 °C yield 64%... 

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