Acetic Anhydride → 5,6-Diacetoxyindole

HRID 257611Notes

Reaction equation

HRID 257611 reaction equation
[CH2:1]([O:8]C1C(OCC2C=CC=CC=2)=CC(/C=C/N2CCCC2)=C([N+]([O-])=O)C=1)[C:2]1C=CC=CC=1.[OH:33][C:34]1[CH:35]=[C:36]([CH3:41])[CH:37]=[CH:38][C:39]=1[OH:40].[C:42]([O:45]C(=O)C)(=O)[CH3:43].[CH3:49][N:50](C1C=CC=CN=1)C.[H][H]>[Pd].C(OCC)(=O)C.C(N(CC)CC)C>[C:1]([O:33][C:34]1[CH:35]=[C:36]2[C:37](=[CH:38][C:39]=1[O:40][C:42](=[O:45])[CH3:43])[NH:50][CH:49]=[CH:41]2)(=[O:8])[CH3:2]

Participants

9

Reactant 5

HCID 7918Acetic AnhydrideHCID 99584-MethylcatecholHCID 218852-DimethylaminopyridineHCID 118261371-(4,5-Bis(benzyloxy)-2-nitrostyryl)pyrrolidineHCID 178418361HCID 178418361, compound

Product 1

HCID 38058835,6-Diacetoxyindole

Reagents, catalysts & solvents 3

HCID 23938PalladiumCatalystHCID 8471TriethylamineSolventHCID 8857Ethyl AcetateSolvent2×

Procedure

A suspension of 17.2 g of trans-4,5-dibenzyloxy-β-pyrrolidino-2-nitrostyrene (prepared from 3,4-dihydroxytoluene by a modified procedure of U.S. Pat. No. 3,732,245) and 3.4 g of 10% Pd/C catalyst in 200 ml ethyl acetate was shaken at room temperature, under hydrogen atmosphere and at 50 psi, for 5 hours. To this reaction mixture was added a solution of ethyl acetate (100 ml) containing acetic anhydride (24 ml), triethylamine (20 ml) and dimethylaminopyridine (800 mg) which was previously saturated with hydrogen. The resultant mixture was stirred for 30 minutes at room temperature. The catalyst was removed over a layer of Celite and the filtrate was evaporated to give an oily residue to which crushed ice was added. The resulting white precipitate was collected by filtration to give 6.08 g (65%) of DAI: mp 130°-131° C.; HNMR (300 MHz, DMSO-d6)δ 2.24 (s,6H), 6.42 (s,1H), 7.22 (s,1H), 7.32 (s,1H), 7.39 (m, 1H) 11.22 (s,1H).

Workup

  1. customThe catalyst was removed over a layer of Celite
  2. customthe filtrate was evaporated
  3. customto give an oily residue to which
  4. customcrushed ice
  5. additionwas added
  6. filtrationThe resulting white precipitate was collected by filtration
  7. customto give 6.08 g (65%) of DAI

Sources & evidence

ORD record
ord-c797e54ef0984ce99abfa260b3f1b37f
Source dataset
uspto-grants-1993_11
Patent number
US05262546

Reaction notes

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