Iodine → ethyl [(1RS,2RS)-6-methoxy-2-p-methoxyphenyl-1,2,3,4-tetrahydronaphth-1-yl]acetate

HRID 569629Notes

Reaction equation

HRID 569629 reaction equation
[CH3:1][O:2][C:3]1[CH:4]=[C:5]2[C:10](=[CH:11][CH:12]=1)[C:9](=O)[CH:8]([C:14]1[CH:19]=[CH:18][C:17]([O:20][CH3:21])=[CH:16][CH:15]=1)[CH2:7][CH2:6]2.Br[CH2:23][C:24]([O:26][CH2:27][CH3:28])=[O:25].II.[Cl-].[NH4+]>[Zn].C1C=CC=CC=1>[CH3:1][O:2][C:3]1[CH:4]=[C:5]2[C:10](=[CH:11][CH:12]=1)[CH:9]([CH2:23][C:24]([O:26][CH2:27][CH3:28])=[O:25])[CH:8]([C:14]1[CH:15]=[CH:16][C:17]([O:20][CH3:21])=[CH:18][CH:19]=1)[CH2:7][CH2:6]2

Participants

7

Reactant 4

HCID 807IodineHCID 7748Ethyl bromoacetateHCID 25517Ammonium ChlorideHCID 134065432-(4-Methoxyphenyl)-6-methoxy-1-tetralone

Product 1

HCID 19861943ethyl [(1RS,2RS)-6-methoxy-2-p-methoxyphenyl-1,2,3,4-tetrahydronaphth-1-yl]acetate

Reagents, catalysts & solvents 2

HCID 23994ZincCatalystHCID 241BenzeneSolvent

Procedure

A stirred mixture of 3,4-dihydro-6-methoxy-2-p-methoxyphenylnaphthalen-1(2H)-one (10 g.), ethyl bromoacetate (17.8 g.), zinc (11.6 g.), benzene (200 ml.) and one crystal of iodine was heated under reflux under an atmosphere of argon for 10 minutes, allowed to continue to boil until the exothermic reaction subsided, heated again under reflux for a further 10 minutes and then cooled to laboratory temperature. Saturated aqueous ammonium chloride solution (100 ml.) was added, the mixture was filtered and the organic layer of the filtrate was separated, dried and evaporated to dryness. A 10% palladium-on-charcoal catalyst (2 g.) was added to a solution of the residue (13.1 g.) in ethyl acetate (300 ml.) and the mixture was stirred under an atmosphere of hydrogen for 3 hours, filtered, and rehydrogenated with fresh catalyst (2 g.) for 18 hours. The mixture was filtered, the filtrate was evaporated to dryness and the residue was purified by chromatography on a silica gel column using a 25: 1 v/v mixture of toluene and ethyl acetate. The ethyl [(1RS,2RS)-6-methoxy-2-p-methoxyphenyl-1,2,3,4-tetrahydronaphth-1-yl]acetate thus obtained was reduced with lithium aluminium hydride (4.4 g.) by a similar process to that described in Example 7, and the ethanol thus obtained (m.p. 98°-99° C.) was oxidised with pyridinium chlorochromate (8.6 g.) by a similar process to that described in the 6th paragraph of Example 2. There was thus obtained the desired acetaldehyde, m.p. 101°-103° C.

Workup

  1. temperaturewas heated
  2. temperatureunder reflux under an atmosphere of argon for 10 minutes
  3. customto boil until the exothermic reaction
  4. temperatureheated again
  5. temperatureunder reflux for a further 10 minutes
  6. temperaturecooled to laboratory temperature
  7. filtrationthe mixture was filtered
  8. customthe organic layer of the filtrate was separated
  9. customdried
  10. customevaporated to dryness
  11. additionA 10% palladium-on-charcoal catalyst (2 g.) was added to a solution of the residue (13.1 g.) in ethyl acetate (300 ml.)
  12. filtrationfiltered
  13. waitrehydrogenated with fresh catalyst (2 g.) for 18 hours
  14. filtrationThe mixture was filtered
  15. customthe filtrate was evaporated to dryness
  16. customthe residue was purified by chromatography on a silica gel column
  17. additiona 25: 1 v/v mixture of toluene and ethyl acetate

Sources & evidence

ORD record
ord-5ab247ed50b1427390f6ffda0c171b56
Source dataset
uspto-grants-1988_03
Patent number
US04732912

Reaction notes

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