1-Hexanol → Oxindole

HRID 49596

Reaction equation

HRID 49596 reaction equation
[NH:1]1[C:10]2[C:5](=[CH:6][CH:7]=[CH:8][CH:9]=2)[C:3](=O)[C:2]1=NN.C1N2CCN(CC2)C1.C([OH:27])CCCCC>>[NH:1]1[C:10]2[C:5](=[CH:6][CH:7]=[CH:8][CH:9]=2)[CH2:3][C:2]1=[O:27]

Participants

4

Reactant 3

HCID 81031-HexanolHCID 9237DabcoHCID 178514334HCID 178514334, compound

Product 1

HCID 321710OxindoleYield 66.5%

Conditions

Temperature
130 °C

Procedure

14.8 g of isatin (99 mmol, 98.2% purity) were initially charged into a 250 ml three-neck flask and 150 ml of 2-ethylhexanol were added. 6.0 g of hydrazine hydrate (117 mmol; 98% purity) were added with stirring. The reaction mixture was heated to 90° C. for 15 min to form the isatin hydrazone (yellow suspension). The water of reaction was azeotropically removed at 90° C./100 mbar using 1-hexanol. 2.4 g of DABCO (21 mmol, 98%) were then added and the suspension heated to 130° C. for 2.5 h. After the end of the reaction (GC analysis: hydrazone 0.3 area %), 100 ml of 1-hexanol were distilled off (80° C./50 mbar). The remaining solution was cooled to 5° C., the precipitated solid filtered off and dried in a vacuum drying cupboard at 70° C. Altogether, 8.0 g of dry 2-oxindole product (light brown) were obtained which corresponded to an overall yield of 66.5%. Purity: 99.9 area %.

Workup

  1. customwas azeotropically removed at 90° C./100 mbar
  2. distillationwere distilled off (80° C./50 mbar)
  3. temperatureThe remaining solution was cooled to 5° C.
  4. filtrationthe precipitated solid filtered off
  5. customdried in a vacuum
  6. customdrying cupboard at 70° C

Sources & evidence

ORD record
ord-953da88ed0f540a19af68a180edccdba
Source dataset
uspto-grants-2004_03
Patent number
US06706890B2

Linked notes

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