Sodium triacetoxyborohydride → methyl 7-nitro-2,3,9,9a-tetrahydro-1H-pyrrolo[1,2-a]indole-8-carboxylate

HRID 715965Notes

Reaction equation

HRID 715965 reaction equation
[N+:1]([C:4]1[CH:12]=[CH:11][C:10]2[N:9]3[CH2:13][CH2:14][CH2:15][C:8]3=[CH:7][C:6]=2[C:5]=1[C:16]([O:18][CH3:19])=[O:17])([O-:3])=[O:2].C(O[BH-](OC(=O)C)OC(=O)C)(=O)C.[Na+]>C(O)(C(F)(F)F)=O.C1(C)C=CC=CC=1>[N+:1]([C:4]1[CH:12]=[CH:11][C:10]2[N:9]3[CH2:13][CH2:14][CH2:15][CH:8]3[CH2:7][C:6]=2[C:5]=1[C:16]([O:18][CH3:19])=[O:17])([O-:3])=[O:2]

Participants

5

Reactant 2

HCID 5049666Sodium triacetoxyborohydrideHCID 70984130methyl 7-nitro-2,3-dihydro-1H-pyrrolo[1,2-a]indole-8-carboxylate2×

Product 1

HCID 70983689methyl 7-nitro-2,3,9,9a-tetrahydro-1H-pyrrolo[1,2-a]indole-8-carboxylateYield 164.7%

Reagents, catalysts & solvents 2

HCID 1140TolueneSolventHCID 6422Trifluoroacetic acidSolvent

Procedure

Methyl 7-nitro-2,3-dihydro-1H-pyrrolo[1,2-a]indole-8-carboxylate (Intermediate 19, 1.00 g) was dissolved in TFA (100 ml) and sodium triacetoxyborohydride (8.11 g) was added. The reaction mixture was stirred at room temperature, then diluted with toluene and concentrated in vacuo. The residue was dissolved in aqueous potassium carbonate solution and extracted with ethyl acetate, dried (MgSO4) and filtered. The filtrate was concentrated in vacuo and the residue was purified by chromatography on silica, eluting with a mixture of methanol and DCM, with a gradient of 0-2% to give methyl 7-nitro-2,3,9,9a-tetrahydro-1H-pyrrolo[1,2-a]indole-8-carboxylate (1.66 g) as a yellow gum.

Workup

  1. concentrationconcentrated in vacuo
  2. dissolutionThe residue was dissolved in aqueous potassium carbonate solution
  3. extractionextracted with ethyl acetate
  4. dry with materialdried (MgSO4)
  5. filtrationfiltered
  6. concentrationThe filtrate was concentrated in vacuo
  7. customthe residue was purified by chromatography on silica
  8. washeluting with a mixture of methanol and DCM, with a gradient of 0-2%

Sources & evidence

ORD record
ord-7bd2c8e6444f4da3a65a1dc3fa5c5150
Source dataset
uspto-grants-2015_11
Patent number
US09187494B2

Reaction notes

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