Water → 4,5-Dihydro-4-oxo-5(phenylmethyl)pyrano[3,2-b]indole-2-carboxylic acid

HRID 26161Notes

Reaction equation

HRID 26161 reaction equation
[O:1]=[C:2]1[C:7]2[N:8]([CH2:15][C:16]3[CH:21]=[CH:20][CH:19]=[CH:18][CH:17]=3)[C:9]3[CH:10]=[CH:11][CH:12]=[CH:13][C:14]=3[C:6]=2[O:5][C:4]([C:22]([O:24]CC)=[O:23])=[CH:3]1.[OH-].[Na+].O>C(O)C>[O:1]=[C:2]1[C:7]2[N:8]([CH2:15][C:16]3[CH:21]=[CH:20][CH:19]=[CH:18][CH:17]=3)[C:9]3[CH:10]=[CH:11][CH:12]=[CH:13][C:14]=3[C:6]=2[O:5][C:4]([C:22]([OH:24])=[O:23])=[CH:3]1

Participants

5

Reactant 3

HCID 962WaterHCID 14798Sodium HydroxideHCID 10020576HCID 10020576, compound

Product 1

HCID 99732184,5-Dihydro-4-oxo-5(phenylmethyl)pyrano[3,2-b]indole-2-carboxylic acid

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent

Procedure

A mixture of 6.0 g (0.017 mole) of ethyl 4,5-dihydro-4-oxo-5-(phenylmethyl)pyrano [3,2-b]indole-2-carboxylate, 80 ml 1% aqueous sodium hydroxide, and 450 ml water was stirred at room temperature for 3 hr. Ethanol (~150 ml) was then added until virtually all of the insoluble material present had dissolved. After washing twice with 250 ml of chloroform, the aqueous layer was filtered by gravity, cooled in ice, and acidified with 4 N hydrochloric acid. The tan precipitate was filtered, digested for 15 min on the steam bath with 100 ml of water and re-filtered while still warm. Recrystallization of the final product from DMF-water yielded a white powder of mpt. 290°-dec.

Workup

  1. dissolutionhad dissolved
  2. washAfter washing twice with 250 ml of chloroform
  3. filtrationthe aqueous layer was filtered by gravity
  4. temperaturecooled in ice
  5. filtrationThe tan precipitate was filtered
  6. waitdigested for 15 min on the steam bath with 100 ml of water
  7. filtrationre-filtered
  8. temperaturewhile still warm
  9. customRecrystallization of the final product from DMF-water
  10. customyielded a white powder of mpt
  11. custom290°-dec

Sources & evidence

ORD record
ord-853ec79016f54535a02bf1f745e581e6
Source dataset
uspto-grants-1979_04
Patent number
US04148806

Reaction notes

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