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With piperidine In ethanol at 90℃; Inert atmosphere
General procedure: The appropriate aldehyde (1 equiv) was added to EtOH (3 mL/0.2 mmol) and the mixture was stirred until complete solution. Theoxindole (1 equiv) and piperidine (0.1 equiv) were added, and themixture was heated to 90°C for 3-7 h, and cooled. The resultingprecipitatewas filtered, washed with cold ethanol and dried to givethe pure compound. If necessary, additional recrystallization inethanol was applied to obtain the pure product.
Reference:
[1] European Journal of Medicinal Chemistry, 2017, vol. 130, p. 286 - 307
[2] Bioorganic and Medicinal Chemistry, 2009, vol. 17, # 5, p. 2077 - 2090
[3] Journal of Chemical Research, 2018, vol. 42, # 5, p. 244 - 246
2
[ 59-48-3 ]
[ 459-57-4 ]
[ 3476-86-6 ]
[ 90828-17-4 ]
Yield
Reaction Conditions
Operation in experiment
25%
With piperidine In ethanol for 3 h; Reflux
General procedure: The preparation of compounds 3-25 was carried out by refluxing oxindole with different aromatic aldehydes in ethanol in the presence of a catalytic amount of piperidine were refluxed for 3 h. After cooling reaction mixture was concentrated at reduced pressure to obtain solid of 3-oxindole derivatives, then washed with 1:1 mixture of hexane-ethyl acetate (25 mL) and dried to afford titles compoundsin good yields (Table 1). Only in two cases (10 and21), both E and Z isomers were obtained, these isomers wereseparated by column chromatography using 1:9 ethyl acetate: hexane as eluent. The structures of synthetic compounds 3-25 were elucidated by 1H NMR and EI MS. Elemental analysis results were also found to be satisfactory.