Methanol → 1-Ethyl-1,3,4,9-tetrahydro-6-(phenylmethoxy)pyrano[3,4-b]indole-1-acetic acid

HRID 484248Notes

Reaction equation

HRID 484248 reaction equation
C[O:2][C:3](=[O:28])[CH2:4][C:5]1([CH2:26][CH3:27])[C:10]2[NH:11][C:12]3[C:17]([C:9]=2[CH2:8][CH2:7][O:6]1)=[CH:16][C:15]([O:18][CH2:19][C:20]1[CH:25]=[CH:24][CH:23]=[CH:22][CH:21]=1)=[CH:14][CH:13]=3.CO.[OH-].[K+]>O>[CH2:26]([C:5]1([CH2:4][C:3]([OH:28])=[O:2])[C:10]2[NH:11][C:12]3[C:17]([C:9]=2[CH2:8][CH2:7][O:6]1)=[CH:16][C:15]([O:18][CH2:19][C:20]1[CH:21]=[CH:22][CH:23]=[CH:24][CH:25]=1)=[CH:14][CH:13]=3)[CH3:27]

Participants

5

Reactant 3

HCID 887MethanolHCID 14797Potassium HydroxideHCID 543507501-Ethyl-1,3,4,9-tetrahydro-6-(phenylmethoxy)pyrano[3,4-b]indole-1-acetic acid methyl ester

Product 1

HCID 199357321-Ethyl-1,3,4,9-tetrahydro-6-(phenylmethoxy)pyrano[3,4-b]indole-1-acetic acidYield 93%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Procedure

A mixture consisting of the ester (29.0 g, 0.0765 mol) of Step A, methanol (800 mL), water (50 mL) and potassium hydroxide (16.0 g, 0.29 mol) is refluxed for 4 hours. The reaction mixture is cooled to room temperature, concentrated and diluted with water (500 mL). The aqueous layer is washed with ether (2×200 mL) and made acidic with a 1:1 mixture of concentrated HCl and water to pH 2.71 is extracted with chloroform (4×300 mL) and the combined chloroform layers are washed once with water (2×300 mL), once with brine (300 mL), dried (MgSO4), filtered and concentrated to give 26.0 g of title compound, m.p. 163°-165° C.

Workup

  1. temperatureis refluxed for 4 hours
  2. concentrationconcentrated
  3. additiondiluted with water (500 mL)
  4. washThe aqueous layer is washed with ether (2×200 mL)
  5. additionmade acidic with a 1:1 mixture of concentrated HCl and water to pH 2.71
  6. extractionis extracted with chloroform (4×300 mL)
  7. washthe combined chloroform layers are washed once with water (2×300 mL), once with brine (300 mL)
  8. dry with materialdried (MgSO4)
  9. filtrationfiltered
  10. concentrationconcentrated

Sources & evidence

ORD record
ord-fb732050ec09468097b39c650e08cfac
Source dataset
uspto-grants-1993_07
Patent number
US05229516

Reaction notes

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