Phenylhydrazine hydrochloride → 2-(4-Methoxyphenyl)-1,2,3,4-tetrahydrocyclopenta[b]indole

HRID 845021Notes

Reaction equation

HRID 845021 reaction equation
[CH3:1][O:2][C:3]1[CH:8]=[CH:7][C:6]([CH:9]2[CH2:13][CH2:12][C:11](=O)[CH2:10]2)=[CH:5][CH:4]=1.Cl.[C:16]1([NH:22]N)[CH:21]=[CH:20][CH:19]=[CH:18][CH:17]=1.COC1C=CC(C2C3C4C=CC=CC=4NC=3CC2)=CC=1>C(O)(=O)C>[CH3:1][O:2][C:3]1[CH:8]=[CH:7][C:6]([CH:9]2[CH2:13][C:12]3[NH:22][C:16]4[CH:17]=[CH:18][CH:19]=[CH:20][C:21]=4[C:11]=3[CH2:10]2)=[CH:5][CH:4]=1

Participants

5

Reactant 3

HCID 60962Phenylhydrazine hydrochlorideHCID 140909103-(4-Methoxyphenyl)cyclopentan-1-oneHCID 20133418HCID 20133418, compound

Product 1

HCID 156113212-(4-Methoxyphenyl)-1,2,3,4-tetrahydrocyclopenta[b]indole

Reagents, catalysts & solvents 1

HCID 176Acetic AcidSolvent

Procedure

A mixture of 3-(4-methoxyphenyl)-1-cyclopentanone (15.21 g) and phenylhydrazine hydrochloride (11.56 g) in glacial acetic acid (110 ml) under nitrogen was stirred magnetically and slowly heated to 90° with a heating mantle. A white precipitate, which formed at approximately 60°, dissolved to give a red solution as the temperature rose exothermically to 110°. As soon as the solid had dissolved, the heating mantle was removed and the temperature allowed to return to 90°. The temperature was then maintained at 90° for 1 hour. The cooled solution was poured into water (400 ml). After refrigeration under nitrogen overnight, the supernatant liquid was filtered. The filter pad and residual material were dissolved in dichloromethane and the solution was washed with saturated sodium bicarbonate solution. The dried (MgSO4) solution was evaporated to a syrup which was subjected to an oil pump vacuum; wt. 18.7 g. This material in dichloromethane was chromatographed on a column of silica gel prepacked in dichloromethane. Elution with dichloromethane afforded a mixture of the titled product and 1,2,3,4-tetrahydro-1-(4-methoxyphenyl)cyclopent[b]indole. After solvent removal, the residual yellow syrup was crystallized from ethanol-hexane to give the titled product as pale yellow crystals; wt. 5.14 g (24.4%), mp=108°-110°.

Workup

  1. temperatureslowly heated to 90° with a heating mantle
  2. customA white precipitate, which formed at approximately 60°
  3. dissolutiondissolved
  4. customto give a red solution as the temperature
  5. customrose exothermically to 110°
  6. dissolutionAs soon as the solid had dissolved
  7. customthe heating mantle was removed
  8. customto return to 90°
  9. temperatureThe temperature was then maintained at 90° for 1 hour
  10. additionThe cooled solution was poured into water (400 ml)
  11. filtrationAfter refrigeration under nitrogen overnight, the supernatant liquid was filtered
  12. dissolutionThe filter pad and residual material were dissolved in dichloromethane
  13. washthe solution was washed with saturated sodium bicarbonate solution
  14. dry with materialThe dried (MgSO4) solution
  15. customwas evaporated to a syrup which
  16. customThis material in dichloromethane was chromatographed on a column of silica gel
  17. washElution with dichloromethane
  18. customafforded

Sources & evidence

ORD record
ord-258a23a00f1a408b890bffaf9a8cd696
Source dataset
uspto-grants-1988_07
Patent number
US04755505

Reaction notes

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