Sodium Hydroxide → 4-Methyl-1-oxo-1,2,3,4-tetrahydropyrazino[1,2-a]indole-7-carboxylic acid

HRID 1710450Notes

Reaction equation

HRID 1710450 reaction equation
C([O:3][C:4]([C:6]1[CH:7]=[CH:8][C:9]2[CH:10]=[C:11]3[C:18](=[O:19])[NH:17][CH2:16][CH:15]([CH3:20])[N:12]3[C:13]=2[CH:14]=1)=[O:5])C.[OH-].[Na+]>C1COCC1.CCO>[CH3:20][CH:15]1[N:12]2[C:13]3[CH:14]=[C:6]([C:4]([OH:5])=[O:3])[CH:7]=[CH:8][C:9]=3[CH:10]=[C:11]2[C:18](=[O:19])[NH:17][CH2:16]1

Participants

4

Reactant 2

HCID 14798Sodium Hydroxide2×HCID 67235749Ethyl 4-methyl-1-oxo-1,2,3,4-tetrahydropyrazino[1,2-a]indole-7-carboxylate

Product 1

HCID 587675714-Methyl-1-oxo-1,2,3,4-tetrahydropyrazino[1,2-a]indole-7-carboxylic acidYield 77%

Reagents, catalysts & solvents 1

HCID 21873804Tetrahydrofuran ethanolSolvent

Conditions

Temperature
75 °C

Procedure

To a suspension of ethyl ester from step d above (3.2 g, 11.75 mmol) in 100 mL of THF/EtOH (1:1 v/v) was added 1 N aq NaOH (43 mL, 43 mmol). The reaction mixture became a clear solution upon addition of 1 N NaOH. The clear solution was heated at 75° C. for 2 h. The reaction was concentrated and the crude residue was dissolved in water, and extracted with ether. The aqueous layer was acidified to pH ˜4 with 3 N HCl (˜16 mL). A large amount of white precipitate formed which was filtered off and rinsed with cold ether. The wet product was dried in the vacum oven (50° C.) to provide 2.2 g of 4-Methyl-1-oxo-1,2,3,4-tetrahydro-pyrazino[1,2-a]indole-7-carboxylic acid, yield 77% for two steps.

Workup

  1. concentrationThe reaction was concentrated
  2. dissolutionthe crude residue was dissolved in water
  3. extractionextracted with ether
  4. customA large amount of white precipitate formed which
  5. filtrationwas filtered off
  6. washrinsed with cold ether
  7. customThe wet product was dried in the vacum oven (50° C.)

Sources & evidence

ORD record
ord-74332686b88e4961841adb7d2eaed21a
Source dataset
uspto-grants-2010_09
Patent number
US07790712B2

Reaction notes

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