Sulfuric Acid → N-(2-methoxy-3,4-methylenedioxybenzyl)-N-(p-toluenesulfonyl)aminoacetaldehyde diethylacetal

HRID 622195Notes

Reaction equation

HRID 622195 reaction equation
[CH2:1]([O:3][CH:4]([O:19][CH2:20][CH3:21])[CH2:5][NH:6][CH2:7][C:8]1[CH:13]=[CH:12][C:11]2[O:14][CH2:15][O:16][C:10]=2[C:9]=1[O:17][CH3:18])[CH3:2].[OH-].[Na+].[S:24](=[O:28])(=O)(O)[OH:25]>>[CH2:20]([O:19][CH:4]([O:3][CH2:1][CH3:2])[CH2:5][N:6]([CH2:7][C:8]1[CH:13]=[CH:12][C:11]2[O:14][CH2:15][O:16][C:10]=2[C:9]=1[O:17][CH3:18])[S:24]([C:11]1[CH:12]=[CH:13][C:8]([CH3:7])=[CH:9][CH:10]=1)(=[O:28])=[O:25])[CH3:21]

Participants

4

Reactant 3

HCID 1118Sulfuric AcidHCID 14798Sodium HydroxideHCID 13911324HCID 13911324, compound

Product 1

HCID 13911325N-(2-methoxy-3,4-methylenedioxybenzyl)-N-(p-toluenesulfonyl)aminoacetaldehyde diethylacetalYield 78%

Conditions

Temperature
5 °C

Procedure

5.67 g (20 mmol) of N-(2-methoxy-3,4-methylenedioxybenzyl)-N-methylaminoacetaldehyde dimethylacetal (1) obtained in Example 3 was dissolved in 40 ml of 6N sulfuric acid. After stirring at 76°-7° C. for 1.5 hours, the reaction mixture was cooled and the pH was controlled to about 11 by adding 25% aqueous solution of sodium hydroxide at a temperature lower than 30° C. It was extracted with 35 ml and then 10 ml of methylene chloride successively, which were combined and washed with 20 ml of water and then dried over anhydrous magnesium sulfate. The solvent was concentrated under vacuum, the residue was dissolved under heating by adding 12 ml of ethanol and then cooled to 5° C. to deposit crystals. The crystals were collected by filtration, washed with 3 ml of cold ethanol and then dried under vacuum to obtain 3.71 g (yield 78%) of 4-hydroxy-8-methoxy-2-methyl-6,7-methylenedioxy-1,2,3,4-tetrahydroisoquinoline (2), m.p. 152°-3° C.

Workup

  1. temperaturethe reaction mixture was cooled
  2. extractionIt was extracted with 35 ml
  3. washwashed with 20 ml of water
  4. dry with materialdried over anhydrous magnesium sulfate
  5. concentrationThe solvent was concentrated under vacuum
  6. dissolutionthe residue was dissolved
  7. temperatureunder heating
  8. additionby adding 12 ml of ethanol
  9. filtrationThe crystals were collected by filtration
  10. washwashed with 3 ml of cold ethanol
  11. customdried under vacuum

Sources & evidence

ORD record
ord-97a73bd2c139415aab11090d0cbabd50
Source dataset
uspto-grants-1988_09
Patent number
US04769480

Reaction notes

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