Sulfuric Acid → 7-amino-6,7-dihydro [5H] benzocycloheptene

HRID 26226Notes

Reaction equation

HRID 26226 reaction equation
S(=O)(=O)(O)O.O[CH:7]1[C:13]2[CH:14]=[CH:15][CH:16]=[CH:17][C:12]=2[CH2:11][CH2:10][CH:9]([NH2:18])[CH2:8]1.O1CCOCC1>O>[NH2:18][CH:9]1[CH:8]=[CH:7][C:13]2[CH:14]=[CH:15][CH:16]=[CH:17][C:12]=2[CH2:11][CH2:10]1

Participants

5

Reactant 3

HCID 1118Sulfuric AcidHCID 312751,4-DioxaneHCID 545180195xi-hydroxy-7-amino-6,7,8,9-tetrahydro [5 H] benzocycloheptene

Product 1

HCID 213252467-amino-6,7-dihydro [5H] benzocyclohepteneYield 59.6%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Conditions

Temperature
20 °C

Procedure

12 ml of 18N sulfuric acid were added to a refluxing mixture of 5.6 g of the product of Step C and 60 ml of dioxane and the mixture was refluxed for 2 hours and then was cooled to 20° C. The mixture was poured into 300 ml of water and the neutral fraction was extracted with ether. The aqueous phase was made alkaline with sodium hydroxide addition and was extracted with ethyl acetate. The ethyl acetate extracts were washed with aqueous sodium chloride solution, dried, filtered and evaporated to dryness to obtain 5 g of raw product. The latter was chromatographed over silica gel and was eluted with an 8-2-1 ethyl acetate-benzene-triethylamine mixture to obtain 3 g of 7-amino-6,7-dihydro [5H] benzocycloheptene in the form of a brown oil.

Workup

  1. temperaturethe mixture was refluxed for 2 hours
  2. extractionthe neutral fraction was extracted with ether
  3. additionwith sodium hydroxide addition
  4. extractionwas extracted with ethyl acetate
  5. washThe ethyl acetate extracts were washed with aqueous sodium chloride solution
  6. customdried
  7. filtrationfiltered
  8. customevaporated to dryness
  9. customto obtain 5 g of raw product
  10. customThe latter was chromatographed over silica gel
  11. washwas eluted with an 8-2-1 ethyl acetate-benzene-triethylamine mixture

Sources & evidence

ORD record
ord-26c83f0667db4e6fa80fd0c67fe6be88
Source dataset
uspto-grants-1979_04
Patent number
US04148919

Reaction notes

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