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

HRID 1026449Notes

Reaction equation

HRID 1026449 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-cc27ca93c42345fcae0b66d1476260f8
Source dataset
uspto-grants-2014_05
Patent number
US08729072B2

Reaction notes

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