1-Pentanol → 1,2,3,3a,8,8a-Hexahydro-alpha-oxo-1,3a,8-trimethyl-5-pyrrolo[2,3-b]indole acetic acid, n-pentyl ester

HRID 1681642Notes

Reaction equation

HRID 1681642 reaction equation
[O:1]=[C:2]([C:8]1[CH:9]=[C:10]2[C:14](=[CH:15][CH:16]=1)[N:13]([CH3:17])[CH:12]1[N:18]([CH3:21])[CH2:19][CH2:20][C:11]21[CH3:22])[C:3]([O:5][CH2:6][CH3:7])=[O:4].[CH2:23](O)[CH2:24][CH2:25]CC>[O-]CC.[Ti+4].[O-]CC.[O-]CC.[O-]CC>[O:1]=[C:2]([C:8]1[CH:9]=[C:10]2[C:14](=[CH:15][CH:16]=1)[N:13]([CH3:17])[CH:12]1[N:18]([CH3:21])[CH2:19][CH2:20][C:11]21[CH3:22])[C:3]([O:5][CH2:6][CH2:7][CH2:23][CH2:24][CH3:25])=[O:4]

Participants

4

Reactant 2

HCID 62761-PentanolHCID 867464181,2,3,3a,8,8a-Hexahydro-alpha-oxo-1,3a,8-trimethyl-5-pyrrolo[2,3-b]indole acetic acid, ethyl ester

Product 1

HCID 867464241,2,3,3a,8,8a-Hexahydro-alpha-oxo-1,3a,8-trimethyl-5-pyrrolo[2,3-b]indole acetic acid, n-pentyl ester

Reagents, catalysts & solvents 1

HCID 76524Titanium tetraethoxideCatalyst

Procedure

A solution of 1,2,3,3a,8,8a-hexahydro-α-oxo-1,3a,8-trimethyl-5-pyrrolo[2,3-b]indole acetic acid, ethyl ester (2.89 g) in 1-pentanol (61 ml) was treated at 0° C. under a nitrogen atmosphere with titanium (IV) ethoxide (0.80 ml). The solution was warmed to room temperature and then slowly heated for 2.5 hours keeping the temperature between 60°-80° C. The excess 1-pentanol was removed by distillation under high vacuum. The residue was washed successively with 50 ml of saturated aqueous NH4Cl solution, two 100 ml portions of saturated aqueous NaHCO3 solution and 50 ml of brine. The organic phase was dried (Na2SO4), filtered and concentrated to afford an oil which was purified by chromatography using preparative HPLC (silica gel, 5% methanol in ethyl acetate). The appropriate fractions were combined and concentrated under vacuum to yield 2.2 g of 1,2,3,3a,8,8a-hexahydro-α-oxo-1,3a,8-trimethyl-5-pyrrolo[2,3-b]indole acetic acid, n-pentyl ester as an oil.

Workup

  1. temperatureslowly heated for 2.5 hours
  2. custombetween 60°-80° C
  3. customThe excess 1-pentanol was removed by distillation under high vacuum
  4. washThe residue was washed successively with 50 ml of saturated aqueous NH4Cl solution, two 100 ml portions of saturated aqueous NaHCO3 solution and 50 ml of brine
  5. dry with materialThe organic phase was dried (Na2SO4)
  6. filtrationfiltered
  7. concentrationconcentrated
  8. customto afford an oil which
  9. customwas purified by chromatography
  10. concentrationconcentrated under vacuum

Sources & evidence

ORD record
ord-e77c9435ceb54649ac63e118d038cc36
Source dataset
uspto-grants-1992_12
Patent number
US05173497

Reaction notes

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