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

HRID 845020Notes

Reaction equation

HRID 845020 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 (15.22 g) and phenyl hydrazine hydrochloride (11.57 g) in glacial acetic acid (112 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° for 1 hr. The cooled solution was poured into 400 ml of water. After refrigeration, the supernatant liquid was filtered. The filter pad and residual material were dissolved in chloroform 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. 19.4 g (92%). This material was chromatographed on a column (60×7.6 cm) of silica gel prepacked in chloroform. Elution with chloroform afforded a mixture of the titled product and 1,2,3,4-tetrahydro-1-(4-methoxyphenyl)-cyclopent[b]indole in a ratio of 3:2 as determined by a reverse phase HPLC system (see Example 2). After solvent removal the residual syrup was coevaporated with acetonitrile to give 11.90 g (56.5%) of a red syrup which began to crystallize on standing. Crystallization from acetonitrile-water (seeding) gave crude product; wt. 5.25 g (24.9%), mp=107°-109°. Recrystallization from acetonitrile-water gave the titled product as pale yellow crystals, wt. 4.39 g, mp=109°-111°.

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. additionThe cooled solution was poured into 400 ml of water
  9. filtrationAfter refrigeration, the supernatant liquid was filtered
  10. dissolutionThe filter pad and residual material were dissolved in chloroform
  11. washthe solution was washed with saturated sodium bicarbonate solution
  12. dry with materialThe dried (MgSO4) solution
  13. customwas evaporated to a syrup which
  14. customThis material was chromatographed on a column (60×7.6 cm) of silica gel
  15. washElution with chloroform
  16. customafforded

Sources & evidence

ORD record
ord-0c3b00362208465281fee3c98607595c
Source dataset
uspto-grants-1988_07
Patent number
US04755505

Reaction notes

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