Acetic Acid → 7,7-Difluoro-3,4,6,7,8,9-hexahydropyrazino[1,2-a]indol-1(2H)-one

HRID 1843206Notes

Reaction equation

HRID 1843206 reaction equation
[NH2:1][CH2:2][CH2:3][N:4]1[C:12]2[CH2:11][C:10]([F:14])([F:13])[CH2:9][CH2:8][C:7]=2[CH:6]=[C:5]1[C:15]([O:17]CC)=O.C(O)(=O)C>C1(C)C=CC=CC=1>[F:13][C:10]1([F:14])[CH2:11][C:12]2[N:4]3[CH2:3][CH2:2][NH:1][C:15](=[O:17])[C:5]3=[CH:6][C:7]=2[CH2:8][CH2:9]1

Participants

4

Reactant 2

HCID 176Acetic AcidHCID 86683733Ethyl 1-(2-Aminoethyl)-6,6-difluoro-4,5,6,7-tetrahydro-1H-indole-2-carboxylate

Product 1

HCID 866837357,7-Difluoro-3,4,6,7,8,9-hexahydropyrazino[1,2-a]indol-1(2H)-oneYield 53.3%

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent

Procedure

Into a 250-mL round-bottom flask was placed a solution of 113n (10 g, 36.73 mmol, 1.00 equiv) in toluene (100 mL) and acetic acid (1.1 g, 18.32 mmol, 0.50 equiv). See FIG. 14. The resulting solution was heated to reflux for 2 h, cooled and concentrated under vacuum. The residue was triturated in 100 mL of dry ether. The crude product was purified by recrystallization from ethanol to afford 4.43 g (53%) of 113o as a white solid. MS-ESI: [M+H]+ 227. 1H NMR (300 MHz, DMSO) δ 2.10-2.24 (2H, m), 2.59-2.64 (2H, m), 3.17-3.27 (2H, m), 3.43-3.48 (2H, m), 3.88-3.92 (2H, m), 6.44 (1H, s), 7.56 (1H, s).

Workup

  1. customInto a 250-mL round-bottom flask was placed
  2. temperatureThe resulting solution was heated
  3. temperatureto reflux for 2 h
  4. temperaturecooled
  5. concentrationconcentrated under vacuum
  6. customThe residue was triturated in 100 mL of dry ether
  7. customThe crude product was purified by recrystallization from ethanol

Sources & evidence

ORD record
ord-4dbe10da3d754baab46c1174f76007dc
Source dataset
uspto-grants-2015_02
Patent number
US08946213B2

Reaction notes

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