Catechol → 1'-ethoxycarbonyl-spiro[1,3-benzodioxole-2,4'-piperidine]

HRID 1377501Notes

Reaction equation

HRID 1377501 reaction equation
[CH2:1]([O:3][C:4]([N:6]1[CH2:11][CH2:10][C:9](=[O:12])[CH2:8][CH2:7]1)=[O:5])[CH3:2].[C:13]1([C:15](=[CH:17][CH:18]=[CH:19][CH:20]=1)O)[OH:14].C1(C)C=CC(S(O)(=O)=O)=CC=1.O>C1(C)C=CC=CC=1>[CH2:1]([O:3][C:4]([N:6]1[CH2:7][CH2:8][C:9]2([O:14][C:13]3[CH:15]=[CH:17][CH:18]=[CH:19][C:20]=3[O:12]2)[CH2:10][CH2:11]1)=[O:5])[CH3:2]

Participants

6

Reactant 4

HCID 289CatecholHCID 962WaterHCID 6101p-Toluenesulfonic acidHCID 34767Ethyl 4-oxo-1-piperidinecarboxylate

Product 1

HCID 104454571'-ethoxycarbonyl-spiro[1,3-benzodioxole-2,4'-piperidine]

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent

Procedure

A mixture of 1-ethoxycarbonyl-4-piperidinone (17 g), pyrocatechol (13 g) and p-toluenesulfonic acid (2.5 g) in 250 ml of dry toluene was refluxed with continuous removal of water. After 3 h the reaction mixture was concentrated in vacuo, 2% NaOH (200 ml) was added followed by extraction with dichloromethane. After drying over magnesium sulfate and removal of solvent in vacuo, the remaining red oil was applied to a silica gel column (eluent:ethyl acetate/heptane=1:1) giving 22 g of a slightly yellow oil, 1'-ethoxycarbonyl-spiro[1,3-benzodioxole-2,4'-piperidine]. The oil was dissolved in ethanol (250 ml), NaOH (10 g) and water (20 ml) were added and the mixture refluxed for 20 h. Removal of the solvents in vacuo addition of salt water followed by extraction with dichloromethane gave, after drying the organic phase over magnesium sulfate and removal of the solvent in vacuo, a red oil which was applied to a silica gel column (eluent:ethyl acetate/methanol/triethylamine =4:5:1 ) yielding 10 g of colorless crystals, spiro[1,3-benzodioxole-2,4'-piperidine], mp: 108°-10° C. The title compound, 25a, prepared from 4-phenyl-1-butyl methanesulfonate (2.3 g) and spiro[1,3-benzodioxole-2,4'-piperidine] (1.9 g) according to the method described in EXAMPLE 2, crystallized as the maleate salt from acetone by addition of maleic acid. Yield: 1.6 g, mp: 156°-57° C.

Workup

  1. concentrationAfter 3 h the reaction mixture was concentrated in vacuo, 2% NaOH (200 ml)
  2. additionwas added
  3. extractionfollowed by extraction with dichloromethane
  4. dry with materialAfter drying over magnesium sulfate and removal of solvent in vacuo

Sources & evidence

ORD record
ord-e697c8a567a74826a7c9da5cc2f3c98b
Source dataset
uspto-grants-1997_09
Patent number
US05665725

Reaction notes

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