HCID 12620579, compound → 5-Methyl-4-oxo-4,5-dihydropyrano[3,2-b]indole-2-carboxylic acid

HRID 2420458Notes

Reaction equation

HRID 2420458 reaction equation
[CH3:1][N:2]1[C:10]2[CH:9]=[CH:8][CH:7]=[CH:6][C:5]=2[C:4]2[O:11][C:12]([C:16]([O:18]CC)=[O:17])=[CH:13][C:14](=[O:15])[C:3]1=2>[OH-].[Na+]>[CH3:1][N:2]1[C:10]2[CH:9]=[CH:8][CH:7]=[CH:6][C:5]=2[C:4]2[O:11][C:12]([C:16]([OH:18])=[O:17])=[CH:13][C:14](=[O:15])[C:3]1=2

Participants

3

Reactant 1

HCID 12620579HCID 12620579, compound

Product 1

HCID 126205845-Methyl-4-oxo-4,5-dihydropyrano[3,2-b]indole-2-carboxylic acid

Reagents, catalysts & solvents 1

HCID 14798Sodium HydroxideSolvent

Procedure

A mixture of 5.40g (0.020 mole) of ethyl 4,5-dihydro-5-methyl-4-oxopyrano[3,2-b]indole-2-carboxylate in 80ml of 1% aqueous sodium hydroxide was stirred at room temperature for 30 min. The nearly one-phase mixture was extracted twice with 50ml CH2Cl2 and the aqueous layer was cooled in ice and acidified with 4N HCl. The gelatinous yellow crude product was filtered, digested for a few minutes on a steam bath with 100ml hot water and then re-filtered. Recrystallization from ab. EtOH gave yellow needles of mpt. 280°-dec.

Workup

  1. extractionThe nearly one-phase mixture was extracted twice with 50ml CH2Cl2
  2. temperaturethe aqueous layer was cooled in ice
  3. filtrationThe gelatinous yellow crude product was filtered
  4. waitdigested for a few minutes on a steam bath with 100ml hot water
  5. filtrationre-filtered
  6. customRecrystallization from ab
  7. customEtOH gave yellow needles of mpt
  8. custom280°-dec

Sources & evidence

ORD record
ord-a6ea5bc234604711ac0f9e72228e7a3b
Source dataset
uspto-grants-1978_08
Patent number
US04110464

Reaction notes

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