Trifluoroacetic acid → 5-nitro-3-(1,2,3,6-tetrahydropyridin-4-yl)-1H-indole

HRID 1186289Notes

Reaction equation

HRID 1186289 reaction equation
[N+:1]([C:4]1[CH:5]=[C:6]2[C:10](=[CH:11][CH:12]=1)[NH:9][CH:8]=[C:7]2[C:13]1[CH2:18][CH2:17][N:16](C(OC(C)(C)C)=O)[CH2:15][CH:14]=1)([O-:3])=[O:2].C(O)(C(F)(F)F)=O>C(Cl)Cl>[N+:1]([C:4]1[CH:5]=[C:6]2[C:10](=[CH:11][CH:12]=1)[NH:9][CH:8]=[C:7]2[C:13]1[CH2:18][CH2:17][NH:16][CH2:15][CH:14]=1)([O-:3])=[O:2]

Participants

4

Reactant 2

HCID 6422Trifluoroacetic acidHCID 54262828tert-Butyl 4-(5-nitro-1H-indol-3-yl)-5,6-dihydropyridine-1(2H)-carboxylate

Product 1

HCID 532635-nitro-3-(1,2,3,6-tetrahydropyridin-4-yl)-1H-indoleYield 99%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

A solution of tert-butyl 4-(5-nitro-1H-indol-3-yl)-5,6-dihydropyridine-1(2H)-carboxylate (0.8 g, 2.330 mmol) in CH2Cl2 (16 mL) was treated with TFA (4 mL) at 0° C. and the resulting mixture was stirred at same temperature for 3 h. The reaction was evaporated and crude was basified with 1 N NaOH solution (pH ˜14). The solid was filtered off, washed with water (2×10 mL). The crude was dried under vacuum and treated with 10% ethyl acetate in hexanes (20 mL). The solid was filtered and washed with hexanes (2×5 mL). The yellow solid was dried under vacuum to obtain 5-nitro-3-(1,2,3,6-tetrahydropyridin-4-yl)-1H-indole (0.56 g, 99%). 1H NMR (DMSO-d6) δ 8.69 (d, 1H, J=2.1 Hz), 8.00 (dd, 1H, J=2.1, 9.0 Hz), 7.63 (s, 1H), 7.55 (d, 1H, J=9.0 Hz), 6.21 (s, 1H), 3.42-3.30 (m, 2H, merged with DMSO-peak), 2.93 (t, 2H, J=5.4 Hz), 2.40-2.30 (m, 2H); ESI-MS (m/z, %): 244 (MH+, 77), 215 (100).

Workup

  1. customThe reaction was evaporated
  2. filtrationThe solid was filtered off
  3. washwashed with water (2×10 mL)
  4. customThe crude was dried under vacuum
  5. additiontreated with 10% ethyl acetate in hexanes (20 mL)
  6. filtrationThe solid was filtered
  7. washwashed with hexanes (2×5 mL)
  8. customThe yellow solid was dried under vacuum

Sources & evidence

ORD record
ord-91fca4883cea40089b508ce72d38e592
Source dataset
uspto-grants-2014_03
Patent number
US08673909B2

Reaction notes

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