Sodium Carbonate → 6,7,8,9-Tetrahydropyrazino[1,2-a]indol-1(2H)-one

HRID 519370Notes

Reaction equation

HRID 519370 reaction equation
C(O[CH:4](OCC)[CH2:5][N:6]1[C:14]2[CH2:13][CH2:12][CH2:11][CH2:10][C:9]=2[CH:8]=[C:7]1[C:15]([NH2:17])=[O:16])C.C(=O)([O-])[O-].[Na+].[Na+]>C(O)(=O)C>[C:15]1(=[O:16])[C:7]2=[CH:8][C:9]3[CH2:10][CH2:11][CH2:12][CH2:13][C:14]=3[N:6]2[CH:5]=[CH:4][NH:17]1

Participants

4

Reactant 2

HCID 10340Sodium CarbonateHCID 866837541-(2,2-Diethoxyethyl)-4,5,6,7-tetrahydro-1H-indole-2-carboxamide

Product 1

HCID 866837556,7,8,9-Tetrahydropyrazino[1,2-a]indol-1(2H)-oneYield 88.5%

Reagents, catalysts & solvents 1

HCID 176Acetic AcidSolvent

Conditions

Temperature
110 °C

Procedure

A mixture of 121d (2.7 g, 9.6 mmol) and acetic acid (10 mL) was heated at 110° C. for 2 h. The mixture was cooled to room temperature and neutralized with aqueous sodium carbonate solution and extracted with ethyl acetate (3×30 mL). The combined organic phase was concentrated under reduced pressure to afford 121e as a yellow solid (1.6 g, 88%). MS-ESI: [M+H]+ 189.3. 1H NMR (500 MHz, DMSO-d6) δ 10.28 (s, 1H), 7.02 (d, J=5.5 Hz, 1H), 6.63 (s, 1H), 6.52 (pt, J=5.5 Hz, 1H), 2.66 (t, J=6.0 Hz, 2H), 2.57 (t, J=6.0 Hz, 2H), 1.83-1.82 (m, 2H), 1.73-1.72 (m, 2H).

Workup

  1. extractionextracted with ethyl acetate (3×30 mL)
  2. concentrationThe combined organic phase was concentrated under reduced pressure

Sources & evidence

ORD record
ord-b633de8647a8474c8ce2f92d294c7559
Source dataset
uspto-grants-2015_08
Patent number
US09115152B2

Reaction notes

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